American River Taxi provides water taxi service between Georgetown, the Southwest Waterfront, and Ballpark Boathouse at Diamond Teague Park, located behind Nationals Park. The new riverwalk trail is also now open to walk from Diamond Teague Park to the Yards Park. Note: As of May 27, 2014, American River Taxi is not providing service to Nationals Park as they wait for delivery of new hovertaxis. Check out the company's Facebook and Twitter pages for updates.
Potomac Riverboat Company runs a Baseball Boat during Nationals home games between Alexandria and Ballpark Boathouse Diamond Teague Park, located behind Nationals Park. Cost is $24 for a round-trip voyage or $15 for one-way. Potomac Riverboat also runs a service between National Harbor and Alexandria, where people can connect to the Baseball Park. Cost is $30 round trip or $20 one way. More information here
Diamond Teague Piers are managed by Gangplank Marina and can be contacted here .