diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 540bd0fdf3..e5d94e0c43 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -12,6 +12,7 @@ Changelog
  * Fix: InlinePanel now handles relations that specify a related_query_name (Aram Dulyan)
  * Fix: before_delete_page / after_delete_page hooks now run within the same database transaction as the page deletion (Tomasz Knapik)
  * Fix: Snippet chooser modal no longer fails on snippet models with UUID primary keys (Sævar Öfjörð Magnússon)
+ * Fix: Restored localisation in date/time pickers (David Moore, Thibaud Colas)
 
 
 2.2.2 (xx.xx.xxxx) - IN DEVELOPMENT
diff --git a/docs/releases/2.3.rst b/docs/releases/2.3.rst
index 299d41c8e2..064884749b 100644
--- a/docs/releases/2.3.rst
+++ b/docs/releases/2.3.rst
@@ -35,7 +35,7 @@ Bug fixes
  * before_delete_page / after_delete_page hooks now run within the same database transaction as the page deletion (Tomasz Knapik)
  * Seek to the beginning of image files when uploading, to restore compatibility with django-storages Google Cloud and Azure backends (Mikalai Radchuk)
  * Snippet chooser modal no longer fails on snippet models with UUID primary keys (Sævar Öfjörð Magnússon)
-
+ * Restored localisation in date/time pickers (David Moore, Thibaud Colas)
 
 Upgrade considerations
 ======================
diff --git a/wagtail/admin/static_src/wagtailadmin/js/page-editor.js b/wagtail/admin/static_src/wagtailadmin/js/page-editor.js
index c148d25cc4..dc42dc54bf 100644
--- a/wagtail/admin/static_src/wagtailadmin/js/page-editor.js
+++ b/wagtail/admin/static_src/wagtailadmin/js/page-editor.js
@@ -32,10 +32,6 @@ function initDateChooser(id, opts) {
             timepicker: false,
             scrollInput: false,
             format: 'Y-m-d',
-            i18n: {
-                lang: window.dateTimePickerTranslations
-            },
-            lang: 'lang',
             onGenerate: hideCurrent
         }, opts || {}));
     } else {
@@ -55,10 +51,6 @@ function initTimeChooser(id) {
             datepicker: false,
             scrollInput: false,
             format: 'H:i',
-            i18n: {
-                lang: window.dateTimePickerTranslations
-            },
-            lang: 'lang'
         });
     } else {
         $('#' + id).datetimepicker({
@@ -74,10 +66,6 @@ function initDateTimeChooser(id, opts) {
             closeOnDateSelect: true,
             format: 'Y-m-d H:i',
             scrollInput: false,
-            i18n: {
-                lang: window.dateTimePickerTranslations
-            },
-            lang: 'lang',
             onGenerate: hideCurrent
         }, opts || {}));
     } else {
diff --git a/wagtail/admin/templates/wagtailadmin/shared/datetimepicker_translations.html b/wagtail/admin/templates/wagtailadmin/shared/datetimepicker_translations.html
index cdbc986388..00d51a3b09 100644
--- a/wagtail/admin/templates/wagtailadmin/shared/datetimepicker_translations.html
+++ b/wagtail/admin/templates/wagtailadmin/shared/datetimepicker_translations.html
@@ -1,7 +1,7 @@
 {% load i18n %}
 
 <script>
-    window.dateTimePickerTranslations = {
+    $.fn.datetimepicker.defaults.i18n.wagtail_custom_locale = {
         months: [
             '{% trans "January" %}',
             '{% trans "February" %}',
@@ -17,6 +17,15 @@
             '{% trans "December" %}'
         ],
         dayOfWeek: [
+            '{% trans "Sunday" %}',
+            '{% trans "Monday" %}',
+            '{% trans "Tuesday" %}',
+            '{% trans "Wednesday" %}',
+            '{% trans "Thursday" %}',
+            '{% trans "Friday" %}',
+            '{% trans "Saturday" %}'
+        ],
+        dayOfWeekShort: [
             '{% trans "Sun" %}',
             '{% trans "Mon" %}',
             '{% trans "Tue" %}',
@@ -24,6 +33,7 @@
             '{% trans "Thu" %}',
             '{% trans "Fri" %}',
             '{% trans "Sat" %}'
-        ]
+        ],
     }
+    $.datetimepicker.setLocale('wagtail_custom_locale');
 </script>
diff --git a/wagtail/contrib/forms/templates/wagtailforms/index_submissions.html b/wagtail/contrib/forms/templates/wagtailforms/index_submissions.html
index f9678128b7..bc6b647d5f 100644
--- a/wagtail/contrib/forms/templates/wagtailforms/index_submissions.html
+++ b/wagtail/contrib/forms/templates/wagtailforms/index_submissions.html
@@ -10,18 +10,10 @@
             $('#id_date_from').datetimepicker({
                 timepicker: false,
                 format: 'Y-m-d',
-                i18n: {
-                    lang: window.dateTimePickerTranslations
-                },
-                lang: 'lang'
             });
             $('#id_date_to').datetimepicker({
                 timepicker: false,
                 format: 'Y-m-d',
-                i18n: {
-                    lang: window.dateTimePickerTranslations
-                },
-                lang: 'lang'
             });
 
             var selectAllCheckbox = document.getElementById('select-all');