diff --git a/migrations/2025-09-19-132648-0000_theme-instance-default/down.sql b/migrations/2025-09-19-132648-0000_theme-instance-default/down.sql
new file mode 100644
index 000000000..070c99b5a
--- /dev/null
+++ b/migrations/2025-09-19-132648-0000_theme-instance-default/down.sql
@@ -0,0 +1,14 @@
+UPDATE
+    local_user
+SET
+    theme = 'browser'
+WHERE
+    theme = 'instance';
+
+UPDATE
+    local_user
+SET
+    theme = 'browser-compact'
+WHERE
+    theme = 'instance-compact';
+
diff --git a/migrations/2025-09-19-132648-0000_theme-instance-default/up.sql b/migrations/2025-09-19-132648-0000_theme-instance-default/up.sql
new file mode 100644
index 000000000..871da5803
--- /dev/null
+++ b/migrations/2025-09-19-132648-0000_theme-instance-default/up.sql
@@ -0,0 +1,14 @@
+UPDATE
+    local_user
+SET
+    theme = 'instance'
+WHERE
+    theme = 'browser';
+
+UPDATE
+    local_user
+SET
+    theme = 'instance-compact'
+WHERE
+    theme = 'browser-compact';
+