diff --git a/.gitignore b/.gitignore
index a6d27108..3dc61b62 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 .idea
+.phpunit.cache
 .phpunit.result.cache
 .php-cs-fixer.cache
 vendor/
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 04eb81b8..78dcadb0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres
 to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [3.0.2] - 2025-02-27
+
+### Added
+
+- Support for SignUp Plus authentication link creation
+- Support for SignUp Plus user data retrieval
+
 ## [3.0.1] - 2025-01-09
 
 ### Changed
diff --git a/README.md b/README.md
index 01ead03e..d49499f0 100644
--- a/README.md
+++ b/README.md
@@ -34,10 +34,11 @@
 10. [Payouts](#payouts)
 11. [Merchant accounts](#merchant-accounts)
 12. [Account identifiers](#account-identifiers)
-13. [Receiving webhook notifications](#webhooks)
-14. [Custom idempotency keys](#idempotency)
-15. [Custom API calls](#custom-api-calls)
-16. [Error Handling](#error-handling)
+13. [SignUp Plus](#signup-plus)
+14. [Receiving webhook notifications](#webhooks)
+15. [Custom idempotency keys](#idempotency)
+16. [Custom API calls](#custom-api-calls)
+17. [Error Handling](#error-handling)
 
 <a name="why"></a>
 
@@ -1011,6 +1012,29 @@ foreach ($merchantAccount->getAccountIdentifiers() as $accountIdentifier) {
 }
 ```
 
+<a name="signup-plus"></a>
+
+# SignUp Plus
+
+Generating a SignUp Plus authentication link:
+
+```php
+$client->signupPlus()
+    ->authUri()
+    ->paymentId('some_payment_id')
+    ->state('some_state')
+    ->create();
+```
+
+Retrieving user data:
+
+```php
+$response = $client->signupPlus()
+        ->userData()
+        ->paymentId('fake_payment_id')
+        ->retrieve(); // SignupPlusUserDataRetrievedInterface
+```
+
 <a name="webhooks"></a>
 
 # Receiving webhook notifications
diff --git a/config/bindings.php b/config/bindings.php
index c8240cda..9af12f58 100644
--- a/config/bindings.php
+++ b/config/bindings.php
@@ -9,6 +9,7 @@
     Interfaces\HppInterface::class => 'makeHpp',
 
     Interfaces\AddressInterface::class => Entities\Address::class,
+    Interfaces\AddressRetrievedInterface::class => Entities\AddressRetrieved::class,
     Interfaces\UserInterface::class => Entities\User::class,
 
     Interfaces\Payment\Beneficiary\BeneficiaryBuilderInterface::class => Entities\Payment\Beneficiary\BeneficiaryBuilder::class,
@@ -109,5 +110,12 @@
     Interfaces\Webhook\Beneficiary\ExternalAccountBeneficiaryInterface::class => Entities\Webhook\Beneficiary\ExternalAccountBeneficiary::class,
     Interfaces\Webhook\Beneficiary\BeneficiaryInterface::class => Entities\Webhook\Beneficiary\Beneficiary::class,
 
+    Interfaces\SignupPlus\SignupPlusBuilderInterface::class => Entities\SignupPlus\SignupPlusBuilder::class,
+    Interfaces\SignupPlus\SignupPlusAuthUriRequestInterface::class => Entities\SignupPlus\SignupPlusAuthUriRequest::class,
+    Interfaces\SignupPlus\SignupPlusAuthUriCreatedInterface::class => Entities\SignupPlus\SignupPlusAuthUriCreated::class,
+    Interfaces\SignupPlus\SignupPlusAccountDetailsInterface::class => Entities\SignupPlus\SignupPlusAccountDetails::class,
+    Interfaces\SignupPlus\SignupPlusUserDataRequestInterface::class => Entities\SignupPlus\SignupPlusUserDataRequest::class,
+    Interfaces\SignupPlus\SignupPlusUserDataRetrievedInterface::class => Entities\SignupPlus\SignupPlusUserDataRetrieved::class,
+
     Interfaces\RequestOptionsInterface::class => Entities\RequestOptions::class,
 ];
diff --git a/src/Constants/Endpoints.php b/src/Constants/Endpoints.php
index 49048e83..adc713a1 100644
--- a/src/Constants/Endpoints.php
+++ b/src/Constants/Endpoints.php
@@ -35,4 +35,7 @@ class Endpoints
 
     public const PAYOUTS_CREATE = '/v3/payouts';
     public const PAYOUTS_RETRIEVE = '/v3/payouts/{id}';
+    public const SIGNUP_PLUS_AUTH = '/signup-plus/authuri';
+    public const SIGNUP_PLUS_PAYMENTS = '/signup-plus/payments?payment_id={id}';
+    public const SIGNUP_PLUS_MANDATES = '/signup-plus/mandates?mandate_id={id}';
 }
diff --git a/src/Entities/Address.php b/src/Entities/Address.php
index 6c20f51c..b4f1d9ad 100644
--- a/src/Entities/Address.php
+++ b/src/Entities/Address.php
@@ -6,58 +6,8 @@
 
 use TrueLayer\Interfaces\AddressInterface;
 
-class Address extends Entity implements AddressInterface
+class Address extends AddressRetrieved implements AddressInterface
 {
-    /**
-     * @var string
-     */
-    protected string $addressLine1;
-
-    /**
-     * @var string
-     */
-    protected string $addressLine2;
-
-    /**
-     * @var string
-     */
-    protected string $city;
-
-    /**
-     * @var string
-     */
-    protected string $state;
-
-    /**
-     * @var string
-     */
-    protected string $zip;
-
-    /**
-     * @var string
-     */
-    protected string $countryCode;
-
-    /**
-     * @var string[]
-     */
-    protected array $arrayFields = [
-        'address_line1',
-        'address_line2',
-        'city',
-        'state',
-        'zip',
-        'country_code',
-    ];
-
-    /**
-     * @return string|null
-     */
-    public function getAddressLine1(): ?string
-    {
-        return $this->addressLine1 ?? null;
-    }
-
     /**
      * @param string $addressLine1
      *
@@ -70,14 +20,6 @@ public function addressLine1(string $addressLine1): AddressInterface
         return $this;
     }
 
-    /**
-     * @return string|null
-     */
-    public function getAddressLine2(): ?string
-    {
-        return $this->addressLine2 ?? null;
-    }
-
     /**
      * @param string $addressLine2
      *
@@ -90,14 +32,6 @@ public function addressLine2(string $addressLine2): AddressInterface
         return $this;
     }
 
-    /**
-     * @return string|null
-     */
-    public function getCity(): ?string
-    {
-        return $this->city ?? null;
-    }
-
     /**
      * @param string $city
      *
@@ -110,14 +44,6 @@ public function city(string $city): AddressInterface
         return $this;
     }
 
-    /**
-     * @return string|null
-     */
-    public function getState(): ?string
-    {
-        return $this->state ?? null;
-    }
-
     /**
      * @param string $state
      *
@@ -130,14 +56,6 @@ public function state(string $state): AddressInterface
         return $this;
     }
 
-    /**
-     * @return string|null
-     */
-    public function getZip(): ?string
-    {
-        return $this->zip ?? null;
-    }
-
     /**
      * @param string $zip
      *
@@ -150,14 +68,6 @@ public function zip(string $zip): AddressInterface
         return $this;
     }
 
-    /**
-     * @return string|null
-     */
-    public function getCountryCode(): ?string
-    {
-        return $this->countryCode ?? null;
-    }
-
     /**
      * @param string $countryCode
      *
diff --git a/src/Entities/AddressRetrieved.php b/src/Entities/AddressRetrieved.php
new file mode 100644
index 00000000..e875e411
--- /dev/null
+++ b/src/Entities/AddressRetrieved.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Entities;
+
+use TrueLayer\Interfaces\AddressRetrievedInterface;
+
+class AddressRetrieved extends Entity implements AddressRetrievedInterface
+{
+    /**
+     * @var string
+     */
+    protected string $addressLine1;
+
+    /**
+     * @var string
+     */
+    protected string $addressLine2;
+
+    /**
+     * @var string
+     */
+    protected string $city;
+
+    /**
+     * @var string
+     */
+    protected string $state;
+
+    /**
+     * @var string
+     */
+    protected string $zip;
+
+    /**
+     * @var string
+     */
+    protected string $countryCode;
+
+    /**
+     * @var string[]
+     */
+    protected array $arrayFields = [
+        'address_line1',
+        'address_line2',
+        'city',
+        'state',
+        'zip',
+        'country_code',
+    ];
+
+    /**
+     * @return string|null
+     */
+    public function getAddressLine1(): ?string
+    {
+        return $this->addressLine1 ?? null;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAddressLine2(): ?string
+    {
+        return $this->addressLine2 ?? null;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getCity(): ?string
+    {
+        return $this->city ?? null;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getState(): ?string
+    {
+        return $this->state ?? null;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getZip(): ?string
+    {
+        return $this->zip ?? null;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getCountryCode(): ?string
+    {
+        return $this->countryCode ?? null;
+    }
+}
diff --git a/src/Entities/SignupPlus/SignupPlusAccountDetails.php b/src/Entities/SignupPlus/SignupPlusAccountDetails.php
new file mode 100644
index 00000000..20d42989
--- /dev/null
+++ b/src/Entities/SignupPlus/SignupPlusAccountDetails.php
@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Entities\SignupPlus;
+
+use TrueLayer\Entities\Entity;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusAccountDetailsInterface;
+
+class SignupPlusAccountDetails extends Entity implements SignupPlusAccountDetailsInterface
+{
+    /**
+     * @var string
+     */
+    protected string $accountNumber;
+
+    /**
+     * @var string
+     */
+    protected string $sortCode;
+
+    /**
+     * @var string
+     */
+    protected string $iban;
+
+    /**
+     * @var string
+     */
+    protected string $providerId;
+
+    /**
+     * @var string[]
+     */
+    protected array $arrayFields = [
+        'account_number',
+        'sort_code',
+        'iban',
+        'provider_id',
+    ];
+
+    /**
+     * @return string|null
+     */
+    public function getAccountNumber(): ?string
+    {
+        return $this->accountNumber ?? null;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getSortCode(): ?string
+    {
+        return $this->sortCode ?? null;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getIban(): ?string
+    {
+        return $this->iban ?? null;
+    }
+
+    /**
+     * @return string
+     */
+    public function getProviderId(): string
+    {
+        return $this->providerId;
+    }
+}
diff --git a/src/Entities/SignupPlus/SignupPlusAuthUriCreated.php b/src/Entities/SignupPlus/SignupPlusAuthUriCreated.php
new file mode 100644
index 00000000..64ce0ffe
--- /dev/null
+++ b/src/Entities/SignupPlus/SignupPlusAuthUriCreated.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Entities\SignupPlus;
+
+use TrueLayer\Entities\Entity;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusAuthUriCreatedInterface;
+
+class SignupPlusAuthUriCreated extends Entity implements SignupPlusAuthUriCreatedInterface
+{
+    /**
+     * @var string
+     */
+    protected string $authUri;
+
+    /**
+     * @var string[]
+     */
+    protected array $arrayFields = [
+        'auth_uri',
+    ];
+
+    /**
+     * @return string
+     */
+    public function getAuthUri(): string
+    {
+        return $this->authUri;
+    }
+}
diff --git a/src/Entities/SignupPlus/SignupPlusAuthUriRequest.php b/src/Entities/SignupPlus/SignupPlusAuthUriRequest.php
new file mode 100644
index 00000000..805aaaba
--- /dev/null
+++ b/src/Entities/SignupPlus/SignupPlusAuthUriRequest.php
@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Entities\SignupPlus;
+
+use TrueLayer\Entities\Entity;
+use TrueLayer\Exceptions\ApiRequestJsonSerializationException;
+use TrueLayer\Exceptions\ApiResponseUnsuccessfulException;
+use TrueLayer\Exceptions\InvalidArgumentException;
+use TrueLayer\Exceptions\SignerException;
+use TrueLayer\Interfaces\HasApiFactoryInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusAuthUriCreatedInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusAuthUriRequestInterface;
+use TrueLayer\Traits\ProvidesApiFactory;
+
+class SignupPlusAuthUriRequest extends Entity implements SignupPlusAuthUriRequestInterface, HasApiFactoryInterface
+{
+    use ProvidesApiFactory;
+
+    /**
+     * @var string
+     */
+    protected string $paymentId;
+
+    /**
+     * @var string|null
+     */
+    protected ?string $state = null;
+
+    /**
+     * @var string[]
+     */
+    protected array $arrayFields = [
+        'payment_id',
+        'state',
+    ];
+
+    /**
+     * @param string $paymentId
+     *
+     * @return SignupPlusAuthUriRequestInterface
+     */
+    public function paymentId(string $paymentId): SignupPlusAuthUriRequestInterface
+    {
+        $this->paymentId = $paymentId;
+
+        return $this;
+    }
+
+    /**
+     * @param string $state
+     *
+     * @return SignupPlusAuthUriRequestInterface
+     */
+    public function state(string $state): SignupPlusAuthUriRequestInterface
+    {
+        $this->state = $state;
+
+        return $this;
+    }
+
+    /**
+     * @throws ApiResponseUnsuccessfulException
+     * @throws ApiRequestJsonSerializationException
+     * @throws SignerException
+     * @throws InvalidArgumentException
+     *
+     * @return SignupPlusAuthUriCreatedInterface
+     */
+    public function create(): SignupPlusAuthUriCreatedInterface
+    {
+        $data = $this->getApiFactory()->signupPlusApi()->createAuthUri(
+            $this->paymentId,
+            $this->state,
+        );
+
+        return $this->make(SignupPlusAuthUriCreatedInterface::class, $data);
+    }
+}
diff --git a/src/Entities/SignupPlus/SignupPlusBuilder.php b/src/Entities/SignupPlus/SignupPlusBuilder.php
new file mode 100644
index 00000000..d714497d
--- /dev/null
+++ b/src/Entities/SignupPlus/SignupPlusBuilder.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Entities\SignupPlus;
+
+use TrueLayer\Entities\EntityBuilder;
+use TrueLayer\Exceptions\InvalidArgumentException;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusAuthUriRequestInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusBuilderInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusUserDataRequestInterface;
+
+final class SignupPlusBuilder extends EntityBuilder implements SignupPlusBuilderInterface
+{
+    /**
+     * @throws InvalidArgumentException
+     *
+     * @return SignupPlusAuthUriRequestInterface
+     */
+    public function authUri(): SignupPlusAuthUriRequestInterface
+    {
+        return $this->entityFactory->make(SignupPlusAuthUriRequestInterface::class);
+    }
+
+    /**
+     * @throws InvalidArgumentException
+     *
+     * @return SignupPlusUserDataRequestInterface
+     */
+    public function userData(): SignupPlusUserDataRequestInterface
+    {
+        return $this->entityFactory->make(SignupPlusUserDataRequestInterface::class);
+    }
+}
diff --git a/src/Entities/SignupPlus/SignupPlusUserDataRequest.php b/src/Entities/SignupPlus/SignupPlusUserDataRequest.php
new file mode 100644
index 00000000..24b770b4
--- /dev/null
+++ b/src/Entities/SignupPlus/SignupPlusUserDataRequest.php
@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Entities\SignupPlus;
+
+use TrueLayer\Entities\Entity;
+use TrueLayer\Exceptions\ApiRequestJsonSerializationException;
+use TrueLayer\Exceptions\ApiResponseUnsuccessfulException;
+use TrueLayer\Exceptions\InvalidArgumentException;
+use TrueLayer\Exceptions\SignerException;
+use TrueLayer\Interfaces\HasApiFactoryInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusUserDataRequestInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusUserDataRetrievedInterface;
+use TrueLayer\Traits\ProvidesApiFactory;
+
+class SignupPlusUserDataRequest extends Entity implements SignupPlusUserDataRequestInterface, HasApiFactoryInterface
+{
+    use ProvidesApiFactory;
+
+    /**
+     * @var string
+     */
+    protected string $paymentId;
+
+    /**
+     * @var string
+     */
+    protected string $mandateId;
+
+    /**
+     * @param string $paymentId
+     *
+     * @return SignupPlusUserDataRequestInterface
+     */
+    public function paymentId(string $paymentId): SignupPlusUserDataRequestInterface
+    {
+        $this->paymentId = $paymentId;
+
+        return $this;
+    }
+
+    /**
+     * @param string $mandateId
+     *
+     * @return SignupPlusUserDataRequestInterface
+     */
+    public function mandateId(string $mandateId): SignupPlusUserDataRequestInterface
+    {
+        $this->mandateId = $mandateId;
+
+        return $this;
+    }
+
+    /**
+     * @throws ApiRequestJsonSerializationException
+     * @throws ApiResponseUnsuccessfulException
+     * @throws InvalidArgumentException
+     * @throws SignerException
+     *
+     * @return SignupPlusUserDataRetrievedInterface
+     */
+    public function retrieve(): SignupPlusUserDataRetrievedInterface
+    {
+        if (empty($this->paymentId) && empty($this->mandateId)) {
+            throw new ApiRequestJsonSerializationException('You need to pass a payment or mandate id');
+        }
+
+        $data = !empty($this->paymentId)
+            ? $this->getApiFactory()->signupPlusApi()->retrieveUserDataByPaymentId($this->paymentId)
+            : $this->getApiFactory()->signupPlusApi()->retrieveUserDataByMandateId($this->mandateId);
+
+        return $this->make(SignupPlusUserDataRetrievedInterface::class, $data);
+    }
+}
diff --git a/src/Entities/SignupPlus/SignupPlusUserDataRetrieved.php b/src/Entities/SignupPlus/SignupPlusUserDataRetrieved.php
new file mode 100644
index 00000000..22c05a8e
--- /dev/null
+++ b/src/Entities/SignupPlus/SignupPlusUserDataRetrieved.php
@@ -0,0 +1,124 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Entities\SignupPlus;
+
+use TrueLayer\Entities\Entity;
+use TrueLayer\Interfaces\AddressRetrievedInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusAccountDetailsInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusUserDataRetrievedInterface;
+
+class SignupPlusUserDataRetrieved extends Entity implements SignupPlusUserDataRetrievedInterface
+{
+    /**
+     * @var string
+     */
+    protected string $title;
+
+    /**
+     * @var string
+     */
+    protected string $firstName;
+
+    /**
+     * @var string
+     */
+    protected string $lastName;
+
+    /**
+     * @var string
+     */
+    protected string $dateOfBirth;
+
+    /**
+     * @var AddressRetrievedInterface
+     */
+    protected AddressRetrievedInterface $address;
+
+    /**
+     * @var string
+     */
+    protected string $nationalIdentificationNumber;
+
+    /**
+     * @var string
+     */
+    protected string $sex;
+
+    /**
+     * @var SignupPlusAccountDetailsInterface
+     */
+    protected SignupPlusAccountDetailsInterface $accountDetails;
+
+    /**
+     * @var string[]
+     */
+    protected array $casts = [
+        'address' => AddressRetrievedInterface::class,
+        'account_details' => SignupPlusAccountDetailsInterface::class,
+    ];
+
+    /**
+     * @var string[]
+     */
+    protected array $arrayFields = [
+        'title',
+        'first_name',
+        'last_name',
+        'date_of_birth',
+        'address',
+        'national_identification_number',
+        'sex',
+        'account_details',
+    ];
+
+    /**
+     * @return string|null
+     */
+    public function getTitle(): ?string
+    {
+        return $this->title ?? null;
+    }
+
+    public function getFirstName(): string
+    {
+        return $this->firstName;
+    }
+
+    public function getLastName(): string
+    {
+        return $this->lastName;
+    }
+
+    public function getDateOfBirth(): string
+    {
+        return $this->dateOfBirth;
+    }
+
+    public function getAddress(): AddressRetrievedInterface
+    {
+        return $this->address;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getNationalIdentificationNumber(): ?string
+    {
+        return $this->nationalIdentificationNumber ?? null;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getSex(): ?string
+    {
+        return $this->sex ?? null;
+    }
+
+    public function getAccountDetails(): SignupPlusAccountDetailsInterface
+    {
+        return $this->accountDetails;
+    }
+}
diff --git a/src/Factories/ApiFactory.php b/src/Factories/ApiFactory.php
index 9ca51662..b9cde3c8 100644
--- a/src/Factories/ApiFactory.php
+++ b/src/Factories/ApiFactory.php
@@ -7,11 +7,13 @@
 use TrueLayer\Interfaces\Api\MerchantAccountsApiInterface;
 use TrueLayer\Interfaces\Api\PaymentsApiInterface;
 use TrueLayer\Interfaces\Api\PayoutsApiInterface;
+use TrueLayer\Interfaces\Api\SignupPlusApiInterface;
 use TrueLayer\Interfaces\ApiClient\ApiClientInterface;
 use TrueLayer\Interfaces\Factories\ApiFactoryInterface;
 use TrueLayer\Services\Api\MerchantAccountsApi;
 use TrueLayer\Services\Api\PaymentsApi;
 use TrueLayer\Services\Api\PayoutsApi;
+use TrueLayer\Services\Api\SignupPlusApi;
 
 final class ApiFactory implements ApiFactoryInterface
 {
@@ -51,4 +53,12 @@ public function payoutsApi(): PayoutsApiInterface
     {
         return new PayoutsApi($this->apiClient);
     }
+
+    /**
+     * @return SignupPlusApiInterface
+     */
+    public function signupPlusApi(): SignupPlusApiInterface
+    {
+        return new SignupPlusApi($this->apiClient);
+    }
 }
diff --git a/src/Interfaces/AddressInterface.php b/src/Interfaces/AddressInterface.php
index dfc301da..9219e83c 100644
--- a/src/Interfaces/AddressInterface.php
+++ b/src/Interfaces/AddressInterface.php
@@ -4,13 +4,8 @@
 
 namespace TrueLayer\Interfaces;
 
-interface AddressInterface extends ArrayableInterface, HasAttributesInterface
+interface AddressInterface extends AddressRetrievedInterface
 {
-    /**
-     * @return string|null
-     */
-    public function getAddressLine1(): ?string;
-
     /**
      * @param string $addressLine1
      *
@@ -18,11 +13,6 @@ public function getAddressLine1(): ?string;
      */
     public function addressLine1(string $addressLine1): AddressInterface;
 
-    /**
-     * @return string|null
-     */
-    public function getAddressLine2(): ?string;
-
     /**
      * @param string $addressLine2
      *
@@ -30,11 +20,6 @@ public function getAddressLine2(): ?string;
      */
     public function addressLine2(string $addressLine2): AddressInterface;
 
-    /**
-     * @return string|null
-     */
-    public function getCity(): ?string;
-
     /**
      * @param string $city
      *
@@ -42,11 +27,6 @@ public function getCity(): ?string;
      */
     public function city(string $city): AddressInterface;
 
-    /**
-     * @return string|null
-     */
-    public function getState(): ?string;
-
     /**
      * @param string $state
      *
@@ -54,11 +34,6 @@ public function getState(): ?string;
      */
     public function state(string $state): AddressInterface;
 
-    /**
-     * @return string|null
-     */
-    public function getZip(): ?string;
-
     /**
      * @param string $zip
      *
@@ -66,11 +41,6 @@ public function getZip(): ?string;
      */
     public function zip(string $zip): AddressInterface;
 
-    /**
-     * @return string|null
-     */
-    public function getCountryCode(): ?string;
-
     /**
      * @param string $countryCode
      *
diff --git a/src/Interfaces/AddressRetrievedInterface.php b/src/Interfaces/AddressRetrievedInterface.php
new file mode 100644
index 00000000..d80d0939
--- /dev/null
+++ b/src/Interfaces/AddressRetrievedInterface.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Interfaces;
+
+interface AddressRetrievedInterface extends ArrayableInterface, HasAttributesInterface
+{
+    /**
+     * @return string|null
+     */
+    public function getAddressLine1(): ?string;
+
+    /**
+     * @return string|null
+     */
+    public function getAddressLine2(): ?string;
+
+    /**
+     * @return string|null
+     */
+    public function getCity(): ?string;
+
+    /**
+     * @return string|null
+     */
+    public function getState(): ?string;
+
+    /**
+     * @return string|null
+     */
+    public function getZip(): ?string;
+
+    /**
+     * @return string|null
+     */
+    public function getCountryCode(): ?string;
+}
diff --git a/src/Interfaces/Api/SignupPlusApiInterface.php b/src/Interfaces/Api/SignupPlusApiInterface.php
new file mode 100644
index 00000000..dfb5d8d5
--- /dev/null
+++ b/src/Interfaces/Api/SignupPlusApiInterface.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Interfaces\Api;
+
+use TrueLayer\Exceptions\ApiRequestJsonSerializationException;
+use TrueLayer\Exceptions\ApiResponseUnsuccessfulException;
+use TrueLayer\Exceptions\SignerException;
+
+interface SignupPlusApiInterface
+{
+    /**
+     * @param string $paymentId
+     * @param string|null $state
+     *
+     * @throws ApiResponseUnsuccessfulException
+     * @throws SignerException
+     * @throws ApiRequestJsonSerializationException
+     *
+     * @return mixed[]
+     */
+    public function createAuthUri(string $paymentId, ?string $state): array;
+
+    /**
+     * @param string $paymentId
+     *
+     * @throws ApiRequestJsonSerializationException
+     * @throws ApiResponseUnsuccessfulException
+     * @throws SignerException
+     *
+     * @return mixed[]
+     */
+    public function retrieveUserDataByPaymentId(string $paymentId): array;
+
+    /**
+     * @param string $mandateId
+     *
+     * @throws ApiRequestJsonSerializationException
+     * @throws ApiResponseUnsuccessfulException
+     * @throws SignerException
+     *
+     * @return mixed[]
+     */
+    public function retrieveUserDataByMandateId(string $mandateId): array;
+}
diff --git a/src/Interfaces/Client/ClientInterface.php b/src/Interfaces/Client/ClientInterface.php
index 6a98b002..09df074f 100644
--- a/src/Interfaces/Client/ClientInterface.php
+++ b/src/Interfaces/Client/ClientInterface.php
@@ -31,6 +31,7 @@
 use TrueLayer\Interfaces\Remitter\RemitterInterface;
 use TrueLayer\Interfaces\Remitter\RemitterVerification\RemitterVerificationBuilderInterface;
 use TrueLayer\Interfaces\RequestOptionsInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusBuilderInterface;
 use TrueLayer\Interfaces\UserInterface;
 use TrueLayer\Interfaces\Webhook\WebhookInterface;
 
@@ -233,4 +234,9 @@ public function hostedPaymentsPage(): HppInterface;
      * @return RequestOptionsInterface
      */
     public function requestOptions(): RequestOptionsInterface;
+
+    /**
+     * @return SignupPlusBuilderInterface
+     */
+    public function signupPlus(): SignupPlusBuilderInterface;
 }
diff --git a/src/Interfaces/Factories/ApiFactoryInterface.php b/src/Interfaces/Factories/ApiFactoryInterface.php
index cfc73d6a..ca402987 100644
--- a/src/Interfaces/Factories/ApiFactoryInterface.php
+++ b/src/Interfaces/Factories/ApiFactoryInterface.php
@@ -7,6 +7,7 @@
 use TrueLayer\Interfaces\Api\MerchantAccountsApiInterface;
 use TrueLayer\Interfaces\Api\PaymentsApiInterface;
 use TrueLayer\Interfaces\Api\PayoutsApiInterface;
+use TrueLayer\Interfaces\Api\SignupPlusApiInterface;
 
 interface ApiFactoryInterface
 {
@@ -24,4 +25,9 @@ public function merchantAccountsApi(): MerchantAccountsApiInterface;
      * @return PayoutsApiInterface
      */
     public function payoutsApi(): PayoutsApiInterface;
+
+    /**
+     * @return SignupPlusApiInterface
+     */
+    public function signupPlusApi(): SignupPlusApiInterface;
 }
diff --git a/src/Interfaces/SignupPlus/SignupPlusAccountDetailsInterface.php b/src/Interfaces/SignupPlus/SignupPlusAccountDetailsInterface.php
new file mode 100644
index 00000000..cabdfc12
--- /dev/null
+++ b/src/Interfaces/SignupPlus/SignupPlusAccountDetailsInterface.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Interfaces\SignupPlus;
+
+use TrueLayer\Interfaces\HasAttributesInterface;
+
+interface SignupPlusAccountDetailsInterface extends HasAttributesInterface
+{
+    /**
+     * @return string|null
+     */
+    public function getAccountNumber(): ?string;
+
+    /**
+     * @return string|null
+     */
+    public function getSortCode(): ?string;
+
+    /**
+     * @return string|null
+     */
+    public function getIban(): ?string;
+
+    /**
+     * @return string
+     */
+    public function getProviderId(): string;
+}
diff --git a/src/Interfaces/SignupPlus/SignupPlusAuthUriCreatedInterface.php b/src/Interfaces/SignupPlus/SignupPlusAuthUriCreatedInterface.php
new file mode 100644
index 00000000..955a51f6
--- /dev/null
+++ b/src/Interfaces/SignupPlus/SignupPlusAuthUriCreatedInterface.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Interfaces\SignupPlus;
+
+use TrueLayer\Interfaces\HasAttributesInterface;
+
+interface SignupPlusAuthUriCreatedInterface extends HasAttributesInterface
+{
+    /**
+     * @return string
+     */
+    public function getAuthUri(): string;
+}
diff --git a/src/Interfaces/SignupPlus/SignupPlusAuthUriRequestInterface.php b/src/Interfaces/SignupPlus/SignupPlusAuthUriRequestInterface.php
new file mode 100644
index 00000000..92f19ff4
--- /dev/null
+++ b/src/Interfaces/SignupPlus/SignupPlusAuthUriRequestInterface.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Interfaces\SignupPlus;
+
+use TrueLayer\Interfaces\HasAttributesInterface;
+
+interface SignupPlusAuthUriRequestInterface extends HasAttributesInterface
+{
+    /**
+     * @param string $paymentId
+     *
+     * @return SignupPlusAuthUriRequestInterface
+     */
+    public function paymentId(string $paymentId): SignupPlusAuthUriRequestInterface;
+
+    /**
+     * @param string $state
+     *
+     * @return SignupPlusAuthUriRequestInterface
+     */
+    public function state(string $state): SignupPlusAuthUriRequestInterface;
+
+    /**
+     * @return SignupPlusAuthUriCreatedInterface
+     */
+    public function create(): SignupPlusAuthUriCreatedInterface;
+}
diff --git a/src/Interfaces/SignupPlus/SignupPlusBuilderInterface.php b/src/Interfaces/SignupPlus/SignupPlusBuilderInterface.php
new file mode 100644
index 00000000..72310b2d
--- /dev/null
+++ b/src/Interfaces/SignupPlus/SignupPlusBuilderInterface.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Interfaces\SignupPlus;
+
+interface SignupPlusBuilderInterface
+{
+    /**
+     * @return SignupPlusAuthUriRequestInterface
+     */
+    public function authUri(): SignupPlusAuthUriRequestInterface;
+
+    /**
+     * @return SignupPlusUserDataRequestInterface
+     */
+    public function userData(): SignupPlusUserDataRequestInterface;
+}
diff --git a/src/Interfaces/SignupPlus/SignupPlusUserDataRequestInterface.php b/src/Interfaces/SignupPlus/SignupPlusUserDataRequestInterface.php
new file mode 100644
index 00000000..4b9ec450
--- /dev/null
+++ b/src/Interfaces/SignupPlus/SignupPlusUserDataRequestInterface.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Interfaces\SignupPlus;
+
+interface SignupPlusUserDataRequestInterface
+{
+    /**
+     * @param string $paymentId
+     *
+     * @return SignupPlusUserDataRequestInterface
+     */
+    public function paymentId(string $paymentId): SignupPlusUserDataRequestInterface;
+
+    /**
+     * @param string $mandateId
+     *
+     * @return SignupPlusUserDataRequestInterface
+     */
+    public function mandateId(string $mandateId): SignupPlusUserDataRequestInterface;
+
+    /**
+     * @return SignupPlusUserDataRetrievedInterface
+     */
+    public function retrieve(): SignupPlusUserDataRetrievedInterface;
+}
diff --git a/src/Interfaces/SignupPlus/SignupPlusUserDataRetrievedInterface.php b/src/Interfaces/SignupPlus/SignupPlusUserDataRetrievedInterface.php
new file mode 100644
index 00000000..dfbc5e35
--- /dev/null
+++ b/src/Interfaces/SignupPlus/SignupPlusUserDataRetrievedInterface.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Interfaces\SignupPlus;
+
+use TrueLayer\Interfaces\AddressRetrievedInterface;
+use TrueLayer\Interfaces\HasAttributesInterface;
+
+interface SignupPlusUserDataRetrievedInterface extends HasAttributesInterface
+{
+    /**
+     * @return string|null
+     */
+    public function getTitle(): ?string;
+
+    /**
+     * @return string
+     */
+    public function getFirstName(): string;
+
+    /**
+     * @return string
+     */
+    public function getLastName(): string;
+
+    /**
+     * @return string
+     */
+    public function getDateOfBirth(): string;
+
+    /**
+     * @return AddressRetrievedInterface
+     */
+    public function getAddress(): AddressRetrievedInterface;
+
+    /**
+     * @return string|null
+     */
+    public function getNationalIdentificationNumber(): ?string;
+
+    /**
+     * @return string|null
+     */
+    public function getSex(): ?string;
+
+    /**
+     * @return SignupPlusAccountDetailsInterface
+     */
+    public function getAccountDetails(): SignupPlusAccountDetailsInterface;
+}
diff --git a/src/Services/Api/SignupPlusApi.php b/src/Services/Api/SignupPlusApi.php
new file mode 100644
index 00000000..83717ac2
--- /dev/null
+++ b/src/Services/Api/SignupPlusApi.php
@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Services\Api;
+
+use TrueLayer\Constants\Endpoints;
+use TrueLayer\Exceptions\ApiRequestJsonSerializationException;
+use TrueLayer\Exceptions\ApiResponseUnsuccessfulException;
+use TrueLayer\Exceptions\SignerException;
+use TrueLayer\Interfaces\Api\SignupPlusApiInterface;
+
+class SignupPlusApi extends Api implements SignupPlusApiInterface
+{
+    /**
+     * @param string $paymentId
+     * @param string|null $state
+     *
+     * @throws ApiRequestJsonSerializationException
+     * @throws ApiResponseUnsuccessfulException
+     * @throws SignerException
+     *
+     * @return mixed[]
+     */
+    public function createAuthUri(string $paymentId, ?string $state): array
+    {
+        return (array) $this->request()
+            ->uri(Endpoints::SIGNUP_PLUS_AUTH)
+            ->payload([
+                'payment_id' => $paymentId,
+                'state' => $state,
+            ])
+            ->post();
+    }
+
+    /**
+     * @param string $paymentId
+     *
+     * @throws SignerException
+     * @throws ApiResponseUnsuccessfulException
+     * @throws ApiRequestJsonSerializationException
+     *
+     * @return mixed[]
+     */
+    public function retrieveUserDataByPaymentId(string $paymentId): array
+    {
+        $uri = \str_replace('{id}', $paymentId, Endpoints::SIGNUP_PLUS_PAYMENTS);
+
+        return (array) $this->request()
+            ->uri($uri)
+            ->get();
+    }
+
+    /**
+     * @param string $mandateId
+     *
+     * @throws ApiRequestJsonSerializationException
+     * @throws ApiResponseUnsuccessfulException
+     * @throws SignerException
+     *
+     * @return array|mixed[]
+     */
+    public function retrieveUserDataByMandateId(string $mandateId): array
+    {
+        $uri = \str_replace('{id}', $mandateId, Endpoints::SIGNUP_PLUS_MANDATES);
+
+        return (array) $this->request()
+            ->uri($uri)
+            ->get();
+    }
+}
diff --git a/src/Services/Client/Client.php b/src/Services/Client/Client.php
index fafca06e..5d80644e 100644
--- a/src/Services/Client/Client.php
+++ b/src/Services/Client/Client.php
@@ -37,6 +37,7 @@
 use TrueLayer\Interfaces\Remitter\RemitterVerification\RemitterVerificationBuilderInterface;
 use TrueLayer\Interfaces\RequestOptionsInterface;
 use TrueLayer\Interfaces\Payment\Scheme\SchemeSelectionBuilderInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusBuilderInterface;
 use TrueLayer\Interfaces\UserInterface;
 use TrueLayer\Interfaces\Webhook\WebhookInterface;
 use TrueLayer\Services\Util\PaymentId;
@@ -424,4 +425,14 @@ public function requestOptions(): RequestOptionsInterface
     {
         return $this->entityFactory->make(RequestOptionsInterface::class);
     }
+
+    /**
+     * @throws InvalidArgumentException
+     *
+     * @return SignupPlusBuilderInterface
+     */
+    public function signupPlus(): SignupPlusBuilderInterface
+    {
+        return $this->entityFactory->make(SignupPlusBuilderInterface::class);
+    }
 }
diff --git a/tests/integration/Mocks/SignupPlusResponse.php b/tests/integration/Mocks/SignupPlusResponse.php
new file mode 100644
index 00000000..c8b2300e
--- /dev/null
+++ b/tests/integration/Mocks/SignupPlusResponse.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TrueLayer\Tests\Integration\Mocks;
+
+use GuzzleHttp\Psr7\Response;
+
+class SignupPlusResponse
+{
+    public static function authUriCreated(): Response
+    {
+        return new Response(201, [], '{"auth_uri":"https://demo-api.gii.cloud/api/oauth/auth_proxy?id=863619242079485953&uuid=b912cc0d-149b-40a2-8a24-79a9d1f0913e"}');
+    }
+
+    public static function userDataRetrievedFinland(): Response
+    {
+        return new Response(200, [], '{"first_name": "Tero Testi","last_name": "Äyrämö","date_of_birth": "1970-01-01","national_identification_number": "010170-1234","sex": "M","address": {"address_line1": "Kauppa Puistikko 6 B 15","city": "VAASA","zip": "65100","country": "FI"},"account_details": {"iban": "FI53CLRB04066200002723","provider_id": "fi-op"}}');
+    }
+
+    public static function userDataRetrievedUk(): Response
+    {
+        return new Response(200, [], '{"title": "Mr","first_name": "Sherlock","last_name": "Holmes","date_of_birth": "1854-01-06","address": {"address_line1": "221B Baker St","address_line2": "Flat 2","city": "London","state": "Greater London","zip": "NW1 6XE","country": "GB"},"account_details": {"account_number": "41921234","sort_code": "04-01-02","iban": "GB71MONZ04435141923452","provider_id": "ob-monzo"}}');
+    }
+}
diff --git a/tests/integration/SignupPlusTest.php b/tests/integration/SignupPlusTest.php
new file mode 100644
index 00000000..49ee1ce1
--- /dev/null
+++ b/tests/integration/SignupPlusTest.php
@@ -0,0 +1,103 @@
+<?php
+
+declare(strict_types=1);
+
+use TrueLayer\Interfaces\AddressRetrievedInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusAccountDetailsInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusAuthUriCreatedInterface;
+use TrueLayer\Interfaces\SignupPlus\SignupPlusUserDataRetrievedInterface;
+use TrueLayer\Tests\Integration\Mocks\SignupPlusResponse;
+
+\it('sends correct payload on signup plus auth link creation', function (string $paymentId, ?string $state) {
+    $client = \client(SignupPlusResponse::authUriCreated());
+
+    $request = $client->signupPlus()
+        ->authUri()
+        ->paymentId($paymentId);
+
+    if (!empty($state)) {
+        $request->state($state);
+    }
+
+    $request->create();
+
+    \expect(\getRequestPayload(1))->toMatchArray([
+        'payment_id' => $paymentId,
+        'state' => $state,
+    ]);
+})->with([
+    'no state' => ['fake_payment_id', null],
+    'with state' => ['fake_payment_id', 'fake_state'],
+]);
+
+\it('parses the signup plus auth uri creation response correctly', function () {
+    $client = \client(SignupPlusResponse::authUriCreated());
+
+    $response = $client->signupPlus()
+        ->authUri()
+        ->paymentId('fake_payment_id')
+        ->state('fake_state')
+        ->create();
+
+    \expect($response)->toBeInstanceOf(SignupPlusAuthUriCreatedInterface::class);
+    \expect($response->getAuthUri())->toBeString();
+});
+
+\it('retrieves the user data by payment id', function () {
+    $client = \client(SignupPlusResponse::userDataRetrievedFinland());
+
+    $response = $client->signupPlus()
+        ->userData()
+        ->paymentId('fake_payment_id')
+        ->retrieve();
+
+    \expect($response)->toBeInstanceOf(SignupPlusUserDataRetrievedInterface::class);
+
+    \expect($response->getTitle())->toBeNull();
+    \expect($response->getFirstName())->toBe('Tero Testi');
+    \expect($response->getLastName())->toBe('Äyrämö');
+    \expect($response->getNationalIdentificationNumber())->toBe('010170-1234');
+    \expect($response->getSex())->toBe('M');
+
+    $address = $response->getAddress();
+    \expect($address)->toBeInstanceOf(AddressRetrievedInterface::class);
+    \expect($address->getAddressLine1())->toBe('Kauppa Puistikko 6 B 15');
+    \expect($address->getCity())->toBe('VAASA');
+    \expect($address->getZip())->toBe('65100');
+
+    $accountDetails = $response->getAccountDetails();
+    \expect($accountDetails)->toBeInstanceOf(SignupPlusAccountDetailsInterface::class);
+    \expect($accountDetails->getIban())->toBe('FI53CLRB04066200002723');
+    \expect($accountDetails->getProviderId())->toBe('fi-op');
+});
+
+\it('retrieves the user data by mandate id', function () {
+    $client = \client(SignupPlusResponse::userDataRetrievedUk());
+
+    $response = $client->signupPlus()
+        ->userData()
+        ->mandateId('fake_mandate_id')
+        ->retrieve();
+
+    \expect($response)->toBeInstanceOf(SignupPlusUserDataRetrievedInterface::class);
+
+    \expect($response->getTitle())->toBe('Mr');
+    \expect($response->getFirstName())->toBe('Sherlock');
+    \expect($response->getLastName())->toBe('Holmes');
+    \expect($response->getDateOfBirth())->toBe('1854-01-06');
+
+    $address = $response->getAddress();
+    \expect($address)->toBeInstanceOf(AddressRetrievedInterface::class);
+    \expect($address->getAddressLine1())->toBe('221B Baker St');
+    \expect($address->getAddressLine2())->toBe('Flat 2');
+    \expect($address->getCity())->toBe('London');
+    \expect($address->getState())->toBe('Greater London');
+    \expect($address->getZip())->toBe('NW1 6XE');
+
+    $accountDetails = $response->getAccountDetails();
+    \expect($accountDetails)->toBeInstanceOf(SignupPlusAccountDetailsInterface::class);
+    \expect($accountDetails->getAccountNumber())->toBe('41921234');
+    \expect($accountDetails->getSortCode())->toBe('04-01-02');
+    \expect($accountDetails->getIban())->toBe('GB71MONZ04435141923452');
+    \expect($accountDetails->getProviderId())->toBe('ob-monzo');
+});