Dozens of operators offer day trips to the Islas del Rosario, which lie between 45 and 90 minutes southwest of the city, depending on the type of boat you’re on. As you cruise past Boca Chica and out into the open sea, don’t miss the 18th-century Spanish fortresses of of San Rafael and San Fernando.
Many of the islands are private; others offer attractions such as the Oceanario, an open-air aquarium and marine museum dedicated more to conservation than entertainment, though rescued dolphins do perform a short show. Most tours end at one of the larger islands: Isla Grande, Isla Rosario, or Isla Caribaru. More secluded spots, such as Isla Los Pajaros, are also on offer.