Database Migration Service is offered at no additional charge for native migrations to Cloud SQL:
|MySQL-native migration or replication to Cloud SQL for MySQL||No additional charge||1,2,3|
|PostgreSQL-native migration or replication to Cloud SQL for PostgreSQL||No additional charge||1,2,3|
Notes on migration pricing
2. Compute Engine VM pricing applies to usage of a virtual machine if created in the context of reverse-SSH connectivity setup.
Migrations from other platforms
3. There's no additional charge for network ingress from external source databases. However, costs can be incurred outside of Google such as platform egress charges.