There are three companies that run ferry trips from Buenos Aires to Colonia: Buquebus, its subsidiary, Seacat; and Colonia Express. All companies offer rides that take 1hr 15 mins.
However, you must take into account that Colonia is not part of the Argentinean territory, and therefore, you should arrive at the port 2 hours before departure for check-in and migrations, especially during peak season. American, European and Latin American citizens don’t need a visa to enter Uruguay, but to be on the safe side, click here to check.
You must also consider the time it will take you to reach the port from your hotel. The trips offered by Buquebus and Seacat depart from Puerto Madero. This port is very accessible and, if you are on a budget you can even get there by metro. Just get off at Catalinas Station and walk a few blocks. The Colonia Express terminal is a bit far from the main hotel areas, in a rather desolate part of town, so we do insist on you taking a cab. Depending on the time of the day, there might be some traffic to contemplate as well.
To check more information about the trip from Buenos Aires to Colonia, click here!