There are dozens of them. It's a very competitive market so bad ones don't last. Most charge around $100 for a 2-tank boat dive. Often the 1st dive is deeper on the wall then a shallower 2nd site. There's over 350 listed sites around the island so most aren't shared. A complete list of operators is at
www.cita.ky
About the only consideration is where you plan to stay. Anywhere along Seven Mile Beach they all pickup - boats are in the marina;s nearby.
Also some sops have officess on-site at resorts. Ambassador Divers is at Comfort Suites another shop is at Sunshine Suites. Divetech is at the Holiday Inn plus their location on the north side at Lighthouse Point.
For boat dives I often reommend Ambassador, Neptune's Diver's or Wall to Wall. Others's recommend Off the Wall. The big boat/cruise diver operations are Don Foster's or Red Sail.
On the quieter Eaast End, Ocean Frontier's or Tortuga Divers. It's about 45-60 minutes out there.
Also Sunset House is an option if you want it all in one place, room, diving, meals. It's also walking distance to downtown Georgetown. Sometimes they offer a single deal that bundles garden view room, boat diving, shrore tanks on prpeerty and breakfast. On the far NW side Cobalt Coast/Reef Divers offer similar options. You'd want a car there - it's 20mins. from anything. There also might be some 1br. condo's at Heppt's Condo's - the Hepp's dive sites are accessible to guests there. Coconut Bay also has Stingray Waterspprts on-site but all the condos are 2-3 bedrooms.
Turtle Reef is also a good, popular shore dive, Sundivers is on site. You may have a harder time finding a buddy there though. Happy Fish Divers offers paid guides there.
Stingray City is the best 15' dive you can do. Also the Kittiwake is done by most operators - it's a big, dive cleaned wreck off the west side.
