Three boats regularly schedule trips there, the Ultimate Getaway, Playmate, and Spree. Ultimate Getaway runs spearfishing or photography charters, Playmate is known for spearfishing, and Spree allows no fishing at all. Juliet has a permit for diving in the park, but all diving must be done live boat, as they are too long to use the moorings, and now that the moorings are installed, anchoring is prohibited. Ultimate Getaway dives in the Sanctuary, but not in the park, Spree dives in both as long as permit requirements are met (fewer than 12 passengers in the Park), otherwise dives in the Sanctuary. Moored dive sites are on patch reefs, there are typically 13 of 36 moorings available at any given time. Reefs tend to be no deeper than 95 feet, and as shallow as 40 feet. There is a wall on the western edge of the sanctuary, as shallow as 60 feet, going as deep as 150 feet. Big stuff tends to be there.
Googling "Dry Tortugas" doesn't get you any information about the actual diving, but try "Dry Tortugas scuba" or "Dry Tortugas diving" for a better response.
