Honduras is world famous for its diving. The Bay Islands are the south-eastern end of the great Mesoamerican Barrier Reef, the second largest in length on the planet, but actually the largest if measured by biodiversity. As such, outstanding diving is to be enjoyed in the entire Bay Islands archipelago.
There are many dive operators in Utila and Roatan, where you can arrange to do anything from becoming a certified open water diver, to specialty courses, and obviously, simply enjoying tank dives if you are already a certified diver.
There is also outstanding diving off the island of Guanaja and the Hog Keys, known locally as Cayos Cochinos. There are not many dive operators at these last two locations, but there are at least a couple of PADI certified outfits at each island. If you are a diver, or interested in experiencing this activity, you should not let the opportunity pass by during your visit to Honduras.