diff --git a/.rubocop.yml b/.rubocop.yml
index b6d8d6047..7af5f1118 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -70,6 +70,7 @@ Naming/UncommunicativeMethodParamName:
     - 'x'
     - 'y'
     - 'on'
+    - 'dt'
 
 Style/ParallelAssignment:
   Enabled: false
diff --git a/lib/capybara/selenium/node.rb b/lib/capybara/selenium/node.rb
index a53665e7f..76b2f79f6 100644
--- a/lib/capybara/selenium/node.rb
+++ b/lib/capybara/selenium/node.rb
@@ -59,11 +59,11 @@ def set(value, **options)
       when 'file'
         set_file(value)
       when 'date'
-        set_date(value)
+        set_date(value, options)
       when 'time'
-        set_time(value)
+        set_time(value, options)
       when 'datetime-local'
-        set_datetime_local(value)
+        set_datetime_local(value, options)
       else
         set_text(value, options)
       end
@@ -256,30 +256,44 @@ def scroll_to_center
     end
   end
 
-  def set_date(value) # rubocop:disable Naming/AccessorMethodName
+  def set_date(value, as_keys: false, **)
     value = SettableValue.new(value)
     return set_text(value) unless value.dateable?
+    return set_as_keystrokes(value, :date) if as_keys
 
-    # TODO: this would be better if locale can be detected and correct keystrokes sent
     update_value_js(value.to_date_str)
   end
 
-  def set_time(value) # rubocop:disable Naming/AccessorMethodName
+  def set_time(value, as_keys: false, **)
     value = SettableValue.new(value)
     return set_text(value) unless value.timeable?
+    return set_as_keystrokes(value, :time) if as_keys
 
-    # TODO: this would be better if locale can be detected and correct keystrokes sent
     update_value_js(value.to_time_str)
   end
 
-  def set_datetime_local(value) # rubocop:disable Naming/AccessorMethodName
+  def set_datetime_local(value, as_keys: false, **)
     value = SettableValue.new(value)
     return set_text(value) unless value.timeable?
+    return set_as_keystrokes(value, :datetime) if as_keys
 
-    # TODO: this would be better if locale can be detected and correct keystrokes sent
     update_value_js(value.to_datetime_str)
   end
 
+  def set_as_keystrokes(val, type)
+    send_keys(keystrokes_for_datetime(val, type))
+  end
+
+  def locale
+    driver.execute_script(<<~JS).to_sym.downcase
+      return (window.navigator && (
+        (window.navigator.languages && window.navigator.languages[0]) ||
+        window.navigator.language ||
+        window.navigator.userLanguage
+      ));
+    JS
+  end
+
   def update_value_js(value)
     driver.execute_script(<<-JS, self, value)
       if (document.activeElement !== arguments[0]){
@@ -354,6 +368,35 @@ def each_key(keys)
     end
   end
 
+  def keystrokes_for_datetime(dt, type)
+    format = LOCALE_KEYSTROKES[locale][type]
+    if format.is_a? String
+      dt.strftime(format)
+    else
+      format.call(dt, self)
+    end
+  end
+
+  LOCALE_KEYSTROKES = {
+    'en-us': {
+      datetime: lambda { |dt, node|
+        if node[:step].empty?
+          dt.strftime '%m%d%Y%t%I%M%p'
+        else
+          dt.strftime '%m%d%Y%t%I%M%S%p'
+        end
+      },
+      time: lambda { |dt, node|
+        if node[:step].empty?
+          dt.strftime '%I%M%p'
+        else
+          dt.strftime '%I%M%S%p'
+        end
+      },
+      date: '%m%d%Y'
+    }
+  }.freeze
+
   # SettableValue encapsulates time/date field formatting
   class SettableValue
     attr_reader :value
@@ -379,11 +422,15 @@ def timeable?
     end
 
     def to_time_str
-      value.to_time.strftime('%H:%M')
+      value.to_time.strftime('%H:%M:%S')
     end
 
     def to_datetime_str
-      value.to_time.strftime('%Y-%m-%dT%H:%M')
+      value.to_time.strftime('%Y-%m-%dT%H:%M:%S')
+    end
+
+    def strftime(format)
+      value.strftime format
     end
   end
   private_constant :SettableValue
diff --git a/lib/capybara/selenium/nodes/marionette_node.rb b/lib/capybara/selenium/nodes/marionette_node.rb
index 803fa3d3a..4c5737bb7 100644
--- a/lib/capybara/selenium/nodes/marionette_node.rb
+++ b/lib/capybara/selenium/nodes/marionette_node.rb
@@ -66,6 +66,12 @@ def click_with_options(click_options)
     super
   end
 
+  def set_as_keystrokes(val, type)
+    # send_keys doesn't work for datetime widgets in FF - use Actions API
+    click(x: 5, y: 5)
+    _send_keys(keystrokes_for_datetime(val, type)).perform
+  end
+
   def _send_keys(keys, actions = browser_action, down_keys = ModifierKeysStack.new)
     case keys
     when :control, :left_control, :right_control,
diff --git a/lib/capybara/spec/session/fill_in_spec.rb b/lib/capybara/spec/session/fill_in_spec.rb
index d60c3b00b..6b18575b8 100644
--- a/lib/capybara/spec/session/fill_in_spec.rb
+++ b/lib/capybara/spec/session/fill_in_spec.rb
@@ -69,12 +69,27 @@
       expect(Time.parse(results).strftime('%r')).to eq time.strftime('%r')
     end
 
+    it 'should fill in a time input with seconds' do
+      time = Time.new(2018, 3, 9, 15, 26, 19)
+      @session.fill_in('form_time_with_seconds', with: time)
+      @session.click_button('awesome')
+      results = extract_results(@session)['time_with_seconds']
+      expect(Time.parse(results).strftime('%r')).to eq time.strftime('%r')
+    end
+
     it 'should fill in a datetime input' do
       dt = Time.new(2018, 3, 13, 9, 53)
       @session.fill_in('form_datetime', with: dt)
       @session.click_button('awesome')
       expect(Time.parse(extract_results(@session)['datetime'])).to eq dt
     end
+
+    it 'should fill in a datetime input with seconds' do
+      dt = Time.new(2018, 3, 13, 9, 53, 13)
+      @session.fill_in('form_datetime_with_seconds', with: dt)
+      @session.click_button('awesome')
+      expect(Time.parse(extract_results(@session)['datetime_with_seconds'])).to eq dt
+    end
   end
 
   it 'should handle HTML in a textarea' do
diff --git a/lib/capybara/spec/views/form.erb b/lib/capybara/spec/views/form.erb
index b95f10523..b8b060813 100644
--- a/lib/capybara/spec/views/form.erb
+++ b/lib/capybara/spec/views/form.erb
@@ -449,6 +449,8 @@ New line after and before textarea tag
     <input type="date" name="form[date]" id="form_date"/>
     <input type="time" name="form[time]" id="form_time"/>
     <input type="datetime-local" name="form[datetime]" id="form_datetime">
+    <input type="time" name="form[time_with_seconds]" id="form_time_with_seconds" step="1">
+    <input type="datetime-local" name="form[datetime_with_seconds]" id="form_datetime_with_seconds" step="1">
   </p>
 
   <p>
diff --git a/spec/shared_selenium_session.rb b/spec/shared_selenium_session.rb
index 6cd475501..65b682cdf 100644
--- a/spec/shared_selenium_session.rb
+++ b/spec/shared_selenium_session.rb
@@ -69,128 +69,179 @@
       end
     end
 
-    context '#fill_in_with empty string and no options' do
-      it 'should trigger change when clearing a field' do
-        session.visit('/with_js')
-        session.fill_in('with_change_event', with: '')
-        # click outside the field to trigger the change event
-        session.find(:css, 'body').click
-        expect(session).to have_selector(:css, '.change_event_triggered', match: :one)
+    describe '#fill_in' do
+      context 'with empty string and no options' do
+        it 'should trigger change when clearing a field' do
+          session.visit('/with_js')
+          session.fill_in('with_change_event', with: '')
+          # click outside the field to trigger the change event
+          session.find(:css, 'body').click
+          expect(session).to have_selector(:css, '.change_event_triggered', match: :one)
+        end
       end
-    end
 
-    context '#fill_in with { :clear => :backspace } fill_option', requires: [:js] do
-      before do
-        # Firefox has an issue with change events if the main window doesn't think it's focused
-        session.execute_script('window.focus()')
-      end
+      context 'with { :clear => :backspace } fill_option', requires: [:js] do
+        before do
+          # Firefox has an issue with change events if the main window doesn't think it's focused
+          session.execute_script('window.focus()')
+        end
 
-      it 'should fill in a field, replacing an existing value' do
-        session.visit('/form')
-        session.fill_in('form_first_name',
-                        with: 'Harry',
-                        fill_options: { clear: :backspace })
-        expect(session.find(:fillable_field, 'form_first_name').value).to eq('Harry')
-      end
+        it 'should fill in a field, replacing an existing value' do
+          session.visit('/form')
+          session.fill_in('form_first_name',
+                          with: 'Harry',
+                          fill_options: { clear: :backspace })
+          expect(session.find(:fillable_field, 'form_first_name').value).to eq('Harry')
+        end
 
-      it 'should fill in a field, replacing an existing value, even with caret position' do
-        session.visit('/form')
-        session.find(:css, '#form_first_name').execute_script <<-JS
-          this.focus();
-          this.setSelectionRange(0, 0);
-        JS
+        it 'should fill in a field, replacing an existing value, even with caret position' do
+          session.visit('/form')
+          session.find(:css, '#form_first_name').execute_script <<-JS
+            this.focus();
+            this.setSelectionRange(0, 0);
+          JS
+
+          session.fill_in('form_first_name',
+                          with: 'Harry',
+                          fill_options: { clear: :backspace })
+          expect(session.find(:fillable_field, 'form_first_name').value).to eq('Harry')
+        end
 
-        session.fill_in('form_first_name',
-                        with: 'Harry',
-                        fill_options: { clear: :backspace })
-        expect(session.find(:fillable_field, 'form_first_name').value).to eq('Harry')
-      end
+        it 'should fill in if the option is set via global option' do
+          Capybara.default_set_options = { clear: :backspace }
+          session.visit('/form')
+          session.fill_in('form_first_name', with: 'Thomas')
+          expect(session.find(:fillable_field, 'form_first_name').value).to eq('Thomas')
+        end
 
-      it 'should fill in if the option is set via global option' do
-        Capybara.default_set_options = { clear: :backspace }
-        session.visit('/form')
-        session.fill_in('form_first_name', with: 'Thomas')
-        expect(session.find(:fillable_field, 'form_first_name').value).to eq('Thomas')
-      end
+        it 'should only trigger onchange once' do
+          session.visit('/with_js')
+          session.fill_in('with_change_event',
+                          with: 'some value',
+                          fill_options: { clear: :backspace })
+          # click outside the field to trigger the change event
+          session.find(:css, '#with_focus_event').click
+          expect(session.find(:css, '.change_event_triggered', match: :one, wait: 5)).to have_text 'some value'
+        end
 
-      it 'should only trigger onchange once' do
-        session.visit('/with_js')
-        session.fill_in('with_change_event',
-                        with: 'some value',
-                        fill_options: { clear: :backspace })
-        # click outside the field to trigger the change event
-        session.find(:css, '#with_focus_event').click
-        expect(session.find(:css, '.change_event_triggered', match: :one, wait: 5)).to have_text 'some value'
-      end
+        it 'should trigger change when clearing field' do
+          session.visit('/with_js')
+          session.fill_in('with_change_event',
+                          with: '',
+                          fill_options: { clear: :backspace })
+          # click outside the field to trigger the change event
+          session.find(:css, '#with_focus_event').click
+          expect(session).to have_selector(:css, '.change_event_triggered', match: :one, wait: 5)
+        end
 
-      it 'should trigger change when clearing field' do
-        session.visit('/with_js')
-        session.fill_in('with_change_event',
-                        with: '',
-                        fill_options: { clear: :backspace })
-        # click outside the field to trigger the change event
-        session.find(:css, '#with_focus_event').click
-        expect(session).to have_selector(:css, '.change_event_triggered', match: :one, wait: 5)
+        it 'should trigger input event field_value.length times' do
+          session.visit('/with_js')
+          session.fill_in('with_change_event',
+                          with: '',
+                          fill_options: { clear: :backspace })
+          # click outside the field to trigger the change event
+          session.find(:css, 'body').click
+          expect(session).to have_xpath('//p[@class="input_event_triggered"]', count: 13)
+        end
       end
 
-      it 'should trigger input event field_value.length times' do
-        session.visit('/with_js')
-        session.fill_in('with_change_event',
-                        with: '',
-                        fill_options: { clear: :backspace })
-        # click outside the field to trigger the change event
-        session.find(:css, 'body').click
-        expect(session).to have_xpath('//p[@class="input_event_triggered"]', count: 13)
+      context 'with { clear: :none } fill_options' do
+        it 'should append to content in a field' do
+          session.visit('/form')
+          session.fill_in('form_first_name',
+                          with: 'Harry',
+                          fill_options: { clear: :none })
+          expect(session.find(:fillable_field, 'form_first_name').value).to eq('JohnHarry')
+        end
       end
-    end
 
-    context '#fill_in with { clear: :none } fill_options' do
-      it 'should append to content in a field' do
-        session.visit('/form')
-        session.fill_in('form_first_name',
-                        with: 'Harry',
-                        fill_options: { clear: :none })
-        expect(session.find(:fillable_field, 'form_first_name').value).to eq('JohnHarry')
-      end
-    end
+      context  'with Date', :focus_ do
+        before do
+          session.visit('/form')
+          session.find(:css, '#form_date').execute_script <<-JS
+            window.capybara_formDateFiredEvents = [];
+            var fd = this;
+            ['focus', 'input', 'change', 'keydown'].forEach(function(eventType) {
+              fd.addEventListener(eventType, function() { window.capybara_formDateFiredEvents.push(eventType); });
+            });
+          JS
+          # work around weird FF issue where it would create an extra focus issue in some cases
+          session.find(:css, 'body').click
+        end
 
-    context  '#fill_in with Date' do
-      before do
-        session.visit('/form')
-        session.find(:css, '#form_date').execute_script <<-JS
-          window.capybara_formDateFiredEvents = [];
-          var fd = this;
-          ['focus', 'input', 'change'].forEach(function(eventType) {
-            fd.addEventListener(eventType, function() { window.capybara_formDateFiredEvents.push(eventType); });
-          });
-        JS
-        # work around weird FF issue where it would create an extra focus issue in some cases
-        session.find(:css, 'body').click
-      end
-
-      it 'should generate standard events on changing value' do
-        pending "IE 11 doesn't support date input type" if ie?(session)
-        session.fill_in('form_date', with: Date.today)
-        expect(session.evaluate_script('window.capybara_formDateFiredEvents')).to eq %w[focus input change]
-      end
-
-      it 'should not generate input and change events if the value is not changed' do
-        pending "IE 11 doesn't support date input type" if ie?(session)
-        session.fill_in('form_date', with: Date.today)
-        session.fill_in('form_date', with: Date.today)
-        # Chrome adds an extra focus for some reason - ok for now
-        expect(session.evaluate_script('window.capybara_formDateFiredEvents')).to eq(%w[focus input change])
+        it 'should generate standard events on changing value' do
+          pending "IE 11 doesn't support date input type" if ie?(session)
+          session.fill_in('form_date', with: Date.today)
+          expect(session.evaluate_script('window.capybara_formDateFiredEvents')).to eq %w[focus input change]
+        end
+
+        it 'should not generate key events without as_keys option' do
+          session.fill_in('form_date', with: Date.today)
+          expect(session.evaluate_script('window.capybara_formDateFiredEvents')).not_to include('keydown')
+        end
+
+        it 'should generate key events with as_keys option' do
+          session.fill_in('form_date', with: Date.today, fill_options: { as_keys: true })
+          expect(session.evaluate_script('window.capybara_formDateFiredEvents')).to include('keydown')
+        end
+
+        it 'should not generate input and change events if the value is not changed' do
+          pending "IE 11 doesn't support date input type" if ie?(session)
+          session.fill_in('form_date', with: Date.today)
+          session.fill_in('form_date', with: Date.today)
+          # Chrome adds an extra focus for some reason - ok for now
+          expect(session.evaluate_script('window.capybara_formDateFiredEvents')).to eq(%w[focus input change])
+        end
+
+        context 'with :as_keys options' do
+          it 'should fill in a date input' do
+            date = Date.today
+            session.fill_in('form_date', with: date, fill_options: { as_keys: true })
+            session.click_button('awesome')
+            expect(Date.parse(extract_results(session)['date'])).to eq date
+          end
+
+          it 'should fill in a time input' do
+            time = Time.new(2019, 2, 11, 7, 3)
+            session.fill_in('form_time', with: time, fill_options: { as_keys: true })
+            session.click_button('awesome')
+            results = extract_results(session)['time']
+            expect(Time.parse(results).strftime('%r')).to eq time.strftime('%r')
+          end
+
+          it 'should fill in a time input with seconds' do
+            time = Time.new(2018, 11, 4, 3, 24, 17)
+            session.fill_in('form_time_with_seconds', with: time, fill_options: { as_keys: true })
+            session.click_button('awesome')
+            results = extract_results(session)['time_with_seconds']
+            expect(Time.parse(results).strftime('%r')).to eq time.strftime('%r')
+          end
+
+          it 'should fill in a datetime input' do
+            dt = Time.new(2018, 10, 13, 12, 53)
+            session.fill_in('form_datetime', with: dt, fill_options: { as_keys: true })
+            session.click_button('awesome')
+            expect(Time.parse(extract_results(session)['datetime'])).to eq dt
+          end
+
+          it 'should fill in a datetime input with seconds' do
+            dt = Time.new(2018, 3, 13, 9, 53, 13)
+            session.fill_in('form_datetime_with_seconds', with: dt, fill_options: { as_keys: true })
+            session.click_button('awesome')
+            expect(Time.parse(extract_results(session)['datetime_with_seconds'])).to eq dt
+          end
+        end
       end
-    end
 
-    context '#fill_in with { clear: Array } fill_options' do
-      it 'should pass the array through to the element' do
-        # this is mainly for use with [[:control, 'a'], :backspace] - however since that is platform dependant I'm testing with something less useful
-        session.visit('/form')
-        session.fill_in('form_first_name',
-                        with: 'Harry',
-                        fill_options: { clear: [[:shift, 'abc'], :backspace] })
-        expect(session.find(:fillable_field, 'form_first_name').value).to eq('JohnABHarry')
+      context 'with { clear: Array } fill_options' do
+        it 'should pass the array through to the element' do
+          # this is mainly for use with [[:control, 'a'], :backspace] - however since that is platform dependant I'm testing with something less useful
+          session.visit('/form')
+          session.fill_in('form_first_name',
+                          with: 'Harry',
+                          fill_options: { clear: [[:shift, 'abc'], :backspace] })
+          expect(session.find(:fillable_field, 'form_first_name').value).to eq('JohnABHarry')
+        end
       end
     end