Vessels crossing the Río de la Plata between Buenos Aires and Uruguay often sell out, particularly on summer weekends. Book a few days ahead at ticket sales offices or with a credit card via phone. Buquebus has twice-daily service for passengers and vehicles between Buenos Aires and Colonia and Montevideo, with continuing bus service to Piriápolis, Punta del Este, and other spots on the Uruguayan coast. The three-hour journey to Colonia costs 100 pesos round trip. The voyage to more distant Montevideo still only takes three hours (the boat's faster) and costs 310 pesos round trip. FerryLineas's twice-daily one-hour hydrofoil trips to Colonia cost 180 pesos round trip. Both companies operate at the same Puerto Madero dock.
Buquebus (Av. Antartida Argentina 821, Puerto Madero. Patio Bullrich Shopping Mall, Av. Libertador 750, La Recoleta. 11/4316-6550. www.buquebus.com). FerryLineas Argentina (Av. Antartida Argentina 821, Puerto Madero. 11/4314-2300. www.ferrylineas.com.uy).