IMO, diving in the USVI has gone downhill in the last decade. I feel like the BVI has a lot more coral left alive. If you have a chance to make it to Virgin Gorda, go with DiveBVI - they're great. Wreck Alley is fun, and they're closer to the Rhone and you're already in British waters vs. going to the Rhone with a US company. I did a night dive with them on the Rhone a couple months ago, since they're close enough to get out there for the night. Also, if you can convince them to take you to the Chikuzen, it's an amazing dive at over 100' with a massive school of resident barracuda.
I will be heading to St Thomas and St John this coming week for a family member's wedding. I'm deliberately going for the entire week to try to do some dives. Does anyone have advice regarding dive operators, locations, shore diving, etc? Any help would be greatly appreciated, and I'll be sure to share my shots when I get back.
Ok, but you asked about the VI. In St. Thomas, I used to dive with Chris Sawyer out of Red Hook, but they recently transitioned to new ownership, so I don't know how they are anymore. Also I have dived out of Hull Bay on the north side with Homer, but last I checked, he wasn't doing dives either. He had a cool night kayak and dive package that was unique, and he also would boat people out to less traveled sites along the North side. I know a professional underwater photographer that hangs out at Secret Harbor and gets amazing macro shots. That is one of the safest beaches/reefs to shore dive or snorkel at night. Safe in terms of low crime... Unrelated to diving, you HAVE to go to Lindquist Bay, now called Smith Bay Park. It is an absolutely gorgeous beach with decent snorkeling.
St. John is frankly a lot nicer than STT these days. I can't recommend a dive company there. I've been with Low Key on two occasions and really wasn't impressed. They aren't bad, they just seemed to be going through the motions a bit. You CAN rent equipment from them relatively cheaply. They recommended that I shore dive at Haulover Bay and Kiddel Bay. I ended up doing both of my dives that day at Haulover because of time constraints. It takes maybe 40 minutes to drive there from Cruz Bay, maybe 30 down to Kiddel and another 40 back to Cruz. The distances are short, but the roads windy! Haulover is in a beautiful location (well what isn't on St. John). It is a rocky beach, so I recommend fins with booties, because walking out in bare feet to put on slipper fins with gear, in breaking waves really hurts. Diving wise, it had some decent coral and was very easy to navigate at about 30' deep even if you had never been there before.
Other places on St. John... there are common places that the dive companies will take you. I've heard at various times of year there are massive starfish migrations around Waterlemon Key, which might be fun to check out. You CAN'T dive at Trunk Bay, which is silly, but there's not really anything there anyway other than beautiful beach, so it's not a big loss. I took a friend there with extra gear to "teach him diving" for a bit and was rudely turned away by the park officer. On St. John, you can also try out windsurfing at Cinnamon with rental gear. Try to just spend some time on the beautiful beaches. I have been approached by two wild dolphins just swimming in Francis Bay. Also, I'll give a plug for "The Fish Trap" restaurant in Cruz Bay. It has awesome seafood. Try the "whole fish" special. You'll get a whole fried fresh fish and sides, it's enough for two people and easily the only good restaurant on St. John you can eat for under $30 per person!
In general in the VI, tourist operators and locals are VERY jaded with tourists. You will get better dives if you insist that you are advanced and do NOT want to go on dives with first timers, etc. Give the dive operators your cell number and tell them to call you if they're running an advanced dive and want to put together a larger group. If you seem like fun, and they don't think you'll pay for average dives, they'll get back to you. When dealing with local people in the tourist industry, always say "Good Morning", "Good Evening", etc. as an introduction. You will get much better service than if you expect them to greet you. It sounds crazy, but I've got years of experience down there and a simple greeting with smile will set you apart from "annoying tourists."
Let me know if you have any other questions or ideas!