diff --git a/docs/migration/v8-to-v9.md b/docs/migration/v8-to-v9.md
index d3951290218a..20c29bbffac3 100644
--- a/docs/migration/v8-to-v9.md
+++ b/docs/migration/v8-to-v9.md
@@ -107,6 +107,7 @@ It will be removed in a future major version.
 - The `getNumberOfUrlSegments` method has been removed. There is no replacement.
 - The `validSeverityLevels` export has been removed. There is no replacement.
 - The `arrayify` export has been removed. There is no replacement.
+- The `flatten` export has been removed. There is no replacement.
 
 ### `@sentry/nestjs`
 
diff --git a/packages/core/src/utils-hoist/array.ts b/packages/core/src/utils-hoist/array.ts
deleted file mode 100644
index 412e22224156..000000000000
--- a/packages/core/src/utils-hoist/array.ts
+++ /dev/null
@@ -1,22 +0,0 @@
-export type NestedArray<T> = Array<NestedArray<T> | T>;
-
-/** Flattens a multi-dimensional array
- *
- * @deprecated This function is deprecated and will be removed in the next major version.
- */
-export function flatten<T>(input: NestedArray<T>): T[] {
-  const result: T[] = [];
-
-  const flattenHelper = (input: NestedArray<T>): void => {
-    input.forEach((el: T | NestedArray<T>) => {
-      if (Array.isArray(el)) {
-        flattenHelper(el as NestedArray<T>);
-      } else {
-        result.push(el as T);
-      }
-    });
-  };
-
-  flattenHelper(input);
-  return result;
-}
diff --git a/packages/core/src/utils-hoist/index.ts b/packages/core/src/utils-hoist/index.ts
index 3bf0f1b9527e..e8cc031f84f7 100644
--- a/packages/core/src/utils-hoist/index.ts
+++ b/packages/core/src/utils-hoist/index.ts
@@ -1,6 +1,4 @@
 export { applyAggregateErrorsToEvent } from './aggregate-errors';
-// eslint-disable-next-line deprecation/deprecation
-export { flatten } from './array';
 export { getBreadcrumbLogLevelFromHttpStatusCode } from './breadcrumb-log-level';
 export { getComponentName, getDomElement, getLocationHref, htmlTreeAsString } from './browser';
 export { dsnFromString, dsnToString, makeDsn } from './dsn';
diff --git a/packages/core/test/utils-hoist/array.test.ts b/packages/core/test/utils-hoist/array.test.ts
deleted file mode 100644
index 3716a6d190b1..000000000000
--- a/packages/core/test/utils-hoist/array.test.ts
+++ /dev/null
@@ -1,67 +0,0 @@
-import type { NestedArray } from '../../src/utils-hoist/array';
-// eslint-disable-next-line deprecation/deprecation
-import { flatten } from '../../src/utils-hoist/array';
-
-describe('flatten', () => {
-  it('should return the same array when input is a flat array', () => {
-    const input = [1, 2, 3, 4];
-    const expected = [1, 2, 3, 4];
-    // eslint-disable-next-line deprecation/deprecation
-    expect(flatten(input)).toEqual(expected);
-  });
-
-  it('should flatten a nested array of numbers', () => {
-    const input = [[1, 2, [3]], 4];
-    const expected = [1, 2, 3, 4];
-    // eslint-disable-next-line deprecation/deprecation
-    expect(flatten(input)).toEqual(expected);
-  });
-
-  it('should flatten a nested array of strings', () => {
-    const input = [
-      ['Hello', 'World'],
-      ['How', 'Are', 'You'],
-    ];
-    const expected = ['Hello', 'World', 'How', 'Are', 'You'];
-    // eslint-disable-next-line deprecation/deprecation
-    expect(flatten(input)).toEqual(expected);
-  });
-
-  it('should flatten a nested array of objects', () => {
-    const input: NestedArray<{ a: number; b?: number } | { b: number; a?: number }> = [
-      [{ a: 1 }, { b: 2 }],
-      [{ a: 3 }, { b: 4 }],
-    ];
-    const expected = [{ a: 1 }, { b: 2 }, { a: 3 }, { b: 4 }];
-    // eslint-disable-next-line deprecation/deprecation
-    expect(flatten(input)).toEqual(expected);
-  });
-
-  it('should flatten a mixed type array', () => {
-    const input: NestedArray<string | { b: number }> = [['a', { b: 2 }, 'c'], 'd'];
-    const expected = ['a', { b: 2 }, 'c', 'd'];
-    // eslint-disable-next-line deprecation/deprecation
-    expect(flatten(input)).toEqual(expected);
-  });
-
-  it('should flatten a deeply nested array', () => {
-    const input = [1, [2, [3, [4, [5]]]]];
-    const expected = [1, 2, 3, 4, 5];
-    // eslint-disable-next-line deprecation/deprecation
-    expect(flatten(input)).toEqual(expected);
-  });
-
-  it('should return an empty array when input is empty', () => {
-    const input: any[] = [];
-    const expected: any[] = [];
-    // eslint-disable-next-line deprecation/deprecation
-    expect(flatten(input)).toEqual(expected);
-  });
-
-  it('should return the same array when input is a flat array', () => {
-    const input = [1, 'a', { b: 2 }, 'c', 3];
-    const expected = [1, 'a', { b: 2 }, 'c', 3];
-    // eslint-disable-next-line deprecation/deprecation
-    expect(flatten(input)).toEqual(expected);
-  });
-});
diff --git a/packages/node/src/utils/redisCache.ts b/packages/node/src/utils/redisCache.ts
index 2a963710e0d5..20cca873c55a 100644
--- a/packages/node/src/utils/redisCache.ts
+++ b/packages/node/src/utils/redisCache.ts
@@ -95,9 +95,8 @@ export function calculateCacheItemSize(response: unknown): number | undefined {
     : getSize(response);
 }
 
-// TODO(v9): This is inlined from core so we can deprecate `flatten`.
-//           It's usage can be replaced with `Array.flat` in v9.
 type NestedArray<T> = Array<NestedArray<T> | T>;
+
 function flatten<T>(input: NestedArray<T>): T[] {
   const result: T[] = [];
 
diff --git a/packages/utils/src/index.ts b/packages/utils/src/index.ts
index 45b540109b14..80dfd17ab72c 100644
--- a/packages/utils/src/index.ts
+++ b/packages/utils/src/index.ts
@@ -62,7 +62,6 @@ import {
   extractTraceparentData as extractTraceparentData_imported,
   filenameIsInApp as filenameIsInApp_imported,
   fill as fill_imported,
-  flatten as flatten_imported,
   forEachEnvelopeItem as forEachEnvelopeItem_imported,
   generatePropagationContext as generatePropagationContext_imported,
   generateSentryTraceHeader as generateSentryTraceHeader_imported,
@@ -599,10 +598,6 @@ export const isNodeEnv = isNodeEnv_imported;
 /** @deprecated Import from `@sentry/core` instead. */
 export const loadModule = loadModule_imported;
 
-/** @deprecated Import from `@sentry/core` instead. */
-// eslint-disable-next-line deprecation/deprecation
-export const flatten = flatten_imported;
-
 /** @deprecated Import from `@sentry/core` instead. */
 // eslint-disable-next-line deprecation/deprecation
 export const memoBuilder = memoBuilder_imported;