The following limitations exist for Amazon RDS encrypted instances: You can only enable encryption for an RDS DB instance when you create it, not after the DB instance is created. Existing DB instances that are not encrypted cannot be modified to enable encryption. DB instances that are encrypted cannot be modified to disable encryption. You cannot have an encrypted Read Replica of an unencrypted DB instance or an unencrypted Read Replica of an encrypted DB instance. Encrypted Read Replicas must be encrypted with the same key as the source DB instance. You cannot restore an unencrypted backup or snapshot to an encrypted DB instance. Because KMS encryption keys are specific to the region that they are created in, you cannot copy an encrypted snapshot from one region to another or replicate encrypted DB instances across regions.