diff --git a/migrations_lockfile.txt b/migrations_lockfile.txt
index d78afee5c9ef22..fdff4a2b285fc7 100644
--- a/migrations_lockfile.txt
+++ b/migrations_lockfile.txt
@@ -39,4 +39,4 @@ tempest: 0003_use_encrypted_char_field
 
 uptime: 0049_cleanup_failed_safe_deletes
 
-workflow_engine: 0102_cleanup_failed_safe_deletes
+workflow_engine: 0103_action_data_fallthrough_type
diff --git a/src/sentry/workflow_engine/migrations/0103_action_data_fallthrough_type.py b/src/sentry/workflow_engine/migrations/0103_action_data_fallthrough_type.py
new file mode 100644
index 00000000000000..547432317530d5
--- /dev/null
+++ b/src/sentry/workflow_engine/migrations/0103_action_data_fallthrough_type.py
@@ -0,0 +1,47 @@
+# Generated by Django 5.2.8 on 2025-11-20 20:02
+
+from django.db import migrations
+from django.db.backends.base.schema import BaseDatabaseSchemaEditor
+from django.db.migrations.state import StateApps
+
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.utils.query import RangeQuerySetWrapper
+
+
+def migrate_fallthrough_type(apps: StateApps, schema_editor: BaseDatabaseSchemaEditor) -> None:
+    Action = apps.get_model("workflow_engine", "Action")
+    for action in RangeQuerySetWrapper(Action.objects.all()):
+        if action.data.get("fallthroughType"):
+            new_data = action.data.copy()
+            del new_data["fallthroughType"]
+            new_data["fallthrough_type"] = action.data["fallthroughType"]
+            action.data = new_data
+            action.save()
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production.
+    # This should only be used for operations where it's safe to run the migration after your
+    # code has deployed. So this should not be used for most operations that alter the schema
+    # of a table.
+    # Here are some things that make sense to mark as post deployment:
+    # - Large data migrations. Typically we want these to be run manually so that they can be
+    #   monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = False
+
+    dependencies = [
+        ("workflow_engine", "0102_cleanup_failed_safe_deletes"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            code=migrate_fallthrough_type,
+            reverse_code=migrations.RunPython.noop,
+            hints={"tables": ["workflow_engine_workflowfirehistory"]},
+        ),
+    ]
diff --git a/tests/sentry/workflow_engine/migrations/test_0103_action_data_fallthrough_type.py b/tests/sentry/workflow_engine/migrations/test_0103_action_data_fallthrough_type.py
new file mode 100644
index 00000000000000..61350135531083
--- /dev/null
+++ b/tests/sentry/workflow_engine/migrations/test_0103_action_data_fallthrough_type.py
@@ -0,0 +1,40 @@
+from sentry.notifications.models.notificationaction import ActionTarget
+from sentry.notifications.types import FallthroughChoiceType
+from sentry.testutils.cases import TestMigrations
+from sentry.workflow_engine.models import Action
+
+
+class TestActionDataFallthroughType(TestMigrations):
+    migrate_from = "0102_cleanup_failed_safe_deletes"
+    migrate_to = "0103_action_data_fallthrough_type"
+    app = "workflow_engine"
+
+    def setup_initial_state(self) -> None:
+        self.org = self.create_organization(name="test-org")
+        self.project = self.create_project(organization=self.org)
+
+        self.action = Action.objects.create(
+            type="email",
+            data={"fallthroughType": FallthroughChoiceType.ACTIVE_MEMBERS},
+            config={
+                "target_type": ActionTarget.ISSUE_OWNERS,
+                "target_identifier": None,
+            },
+        )
+        self.action_no_fallthrough = Action.objects.create(
+            type="email",
+            data={},
+            config={
+                "target_type": ActionTarget.USER,
+                "target_identifier": str(self.user.id),
+            },
+        )
+
+    def test_migration(self) -> None:
+        fallthrough_action = Action.objects.filter(
+            data={"fallthrough_type": FallthroughChoiceType.ACTIVE_MEMBERS}
+        )
+        assert len(fallthrough_action) == 1
+
+        no_fallthrough_action = Action.objects.filter(data={})
+        assert len(no_fallthrough_action) == 1