The Database Migration Service is specifically designed to facilitate the safe and expedient transfer of databases to Amazon Web Services. It supports the ongoing replication feature, which is crucial for maintaining business operations with minimal downtime during the migration process. This contrasts with the Schema Conversion Tool, which is utilized primarily for adapting the database schema for the new service without handling the actual data transfer. Meanwhile, Amazon Athena is a query service that operates on data already in Amazon S3 and does not involve the movement of database workloads. Similarly, Amazon RDS is a managed database service that hosts databases but is not a tool for migration.