diff --git a/migrations_lockfile.txt b/migrations_lockfile.txt
index ca7d37792e64c8..c95f74fece243c 100644
--- a/migrations_lockfile.txt
+++ b/migrations_lockfile.txt
@@ -31,7 +31,7 @@ releases: 0003_real_delete_dual_written_commit_tables
 
 replays: 0006_add_bulk_delete_job
 
-sentry: 1005_add_groupemailthread_project_date_index
+sentry: 1006_drop_legacy_incidentseen_incidentsubscription
 
 social_auth: 0003_social_auth_json_field
 
diff --git a/src/sentry/db/router.py b/src/sentry/db/router.py
index f4be121983b4fe..d86bfab3b93230 100644
--- a/src/sentry/db/router.py
+++ b/src/sentry/db/router.py
@@ -70,6 +70,8 @@ class SiloRouter:
         "authprovider_duplicate": SiloMode.CONTROL,
         "sentry_actor": SiloMode.REGION,
         "sentry_alertruleactivations": SiloMode.REGION,
+        "sentry_incidentseen": SiloMode.REGION,
+        "sentry_incidentsubscription": SiloMode.REGION,
         "sentry_monitorlocation": SiloMode.REGION,
         "sentry_notificationsetting": SiloMode.CONTROL,
         "sentry_pagerdutyservice": SiloMode.REGION,
diff --git a/src/sentry/migrations/1006_drop_legacy_incidentseen_incidentsubscription.py b/src/sentry/migrations/1006_drop_legacy_incidentseen_incidentsubscription.py
new file mode 100644
index 00000000000000..14d4fad42db3f7
--- /dev/null
+++ b/src/sentry/migrations/1006_drop_legacy_incidentseen_incidentsubscription.py
@@ -0,0 +1,39 @@
+# Generated by Django 5.2.8 on 2025-11-18 21:54
+
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.special import SafeRunSQL
+
+
+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 = True
+
+    dependencies = [
+        ("sentry", "1005_add_groupemailthread_project_date_index"),
+    ]
+
+    operations = [
+        SafeRunSQL(
+            """
+            DROP TABLE IF EXISTS sentry_incidentseen CASCADE;
+            """,
+            hints={"tables": ["sentry_incidentseen"]},
+        ),
+        SafeRunSQL(
+            """
+            DROP TABLE IF EXISTS sentry_incidentsubscription CASCADE;
+            """,
+            hints={"tables": ["sentry_incidentsubscription"]},
+        ),
+    ]