Portobelo's bay is one of the better diving destinations on Panama's Caribbean coast, and it is accessible without a boat for much of it. The bay holds several wrecks — including the Buena Vista, a cargo ship resting at around 10 metres — as well as coral reefs with reasonable visibility on calm days. The reefs are close enough to shore that confident snorkellers can reach them from the beach; scuba divers will find the wrecks the main draw.
A small number of dive operators work out of Portobelo and the nearby area. They offer equipment rental, guided dives, and PADI courses. Independent divers with their own gear can simply enter from the shore or hire a local boat for a short ride out to the main sites. Visibility is best in the dry season, roughly January to April, when rain runoff is minimal and the water is calmer.
The rainforest hills surrounding the bay give the diving an unusual character — you surface to find yourself looking up at dense green slopes and ruined fort walls. Outside the festival season, you may have the water to yourself.