diff --git a/polylan_submitter/opus_magnum/migrations/0001_initial.py b/polylan_submitter/opus_magnum/migrations/0001_initial.py
index b725a71..4d462a2 100644
--- a/polylan_submitter/opus_magnum/migrations/0001_initial.py
+++ b/polylan_submitter/opus_magnum/migrations/0001_initial.py
@@ -205,7 +205,7 @@ class Migration(migrations.Migration):
                     models.ForeignKey(
                         on_delete=django.db.models.deletion.CASCADE,
                         related_name="items",
-                        to="submissions.steamcollection",
+                        to="opus_magnum.steamcollection",
                     ),
                 ),
             ],
diff --git a/polylan_submitter/opus_magnum/migrations/0004_submission_puzzleresponse_submissionfile.py b/polylan_submitter/opus_magnum/migrations/0004_submission_puzzleresponse_submissionfile.py
index 27bdb74..9d0a0a5 100644
--- a/polylan_submitter/opus_magnum/migrations/0004_submission_puzzleresponse_submissionfile.py
+++ b/polylan_submitter/opus_magnum/migrations/0004_submission_puzzleresponse_submissionfile.py
@@ -160,7 +160,7 @@ class Migration(migrations.Migration):
                         help_text="The puzzle this response is for",
                         on_delete=django.db.models.deletion.CASCADE,
                         related_name="responses",
-                        to="submissions.steamcollectionitem",
+                        to="opus_magnum.steamcollectionitem",
                     ),
                 ),
                 (
@@ -168,7 +168,7 @@ class Migration(migrations.Migration):
                     models.ForeignKey(
                         on_delete=django.db.models.deletion.CASCADE,
                         related_name="responses",
-                        to="submissions.submission",
+                        to="opus_magnum.submission",
                     ),
                 ),
             ],
@@ -239,7 +239,7 @@ class Migration(migrations.Migration):
                     models.ForeignKey(
                         on_delete=django.db.models.deletion.CASCADE,
                         related_name="files",
-                        to="submissions.puzzleresponse",
+                        to="opus_magnum.puzzleresponse",
                     ),
                 ),
             ],
diff --git a/polylan_submitter/opus_magnum/migrations/0015_migrate_data_from_submissions.py b/polylan_submitter/opus_magnum/migrations/0015_migrate_data_from_submissions.py
new file mode 100644
index 0000000..f90c4e0
--- /dev/null
+++ b/polylan_submitter/opus_magnum/migrations/0015_migrate_data_from_submissions.py
@@ -0,0 +1,67 @@
+# Data migration: Copy all data from submissions app tables to opus_magnum app tables
+
+from django.db import migrations
+
+
+def migrate_data_forward(apps, schema_editor):
+    """Copy data from submissions_* tables to opus_magnum_* tables"""
+    # Use raw SQL to copy data while preserving all fields
+    with schema_editor.connection.cursor() as cursor:
+        # Copy SteamAPIKey
+        cursor.execute("""
+            INSERT INTO opus_magnum_steamapikey
+            SELECT * FROM submissions_steamapikey
+        """)
+
+        # Copy SteamCollection
+        cursor.execute("""
+            INSERT INTO opus_magnum_steamcollection
+            SELECT * FROM submissions_steamcollection
+        """)
+
+        # Copy SteamCollectionItem
+        cursor.execute("""
+            INSERT INTO opus_magnum_steamcollectionitem
+            SELECT * FROM submissions_steamcollectionitem
+        """)
+
+        # Copy Submission
+        cursor.execute("""
+            INSERT INTO opus_magnum_submission
+            SELECT * FROM submissions_submission
+        """)
+
+        # Copy PuzzleResponse
+        cursor.execute("""
+            INSERT INTO opus_magnum_puzzleresponse
+            SELECT * FROM submissions_puzzleresponse
+        """)
+
+        # Copy SubmissionFile
+        cursor.execute("""
+            INSERT INTO opus_magnum_submissionfile
+            SELECT * FROM submissions_submissionfile
+        """)
+
+
+def migrate_data_backward(apps, schema_editor):
+    """Delete all data from opus_magnum_* tables"""
+    with schema_editor.connection.cursor() as cursor:
+        # Delete in reverse order of foreign key dependencies
+        cursor.execute("DELETE FROM opus_magnum_submissionfile")
+        cursor.execute("DELETE FROM opus_magnum_puzzleresponse")
+        cursor.execute("DELETE FROM opus_magnum_submission")
+        cursor.execute("DELETE FROM opus_magnum_steamcollectionitem")
+        cursor.execute("DELETE FROM opus_magnum_steamcollection")
+        cursor.execute("DELETE FROM opus_magnum_steamapikey")
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('opus_magnum', '0014_steamcollection_accepting_submissions'),
+    ]
+
+    operations = [
+        migrations.RunPython(migrate_data_forward, migrate_data_backward),
+    ]