FYI, I work at the dive shop at Morritt's Tortuga Club.
Colliers is in the district of East End - my stomping ground. I'd guess you are probably staying at The Royal Reef or Morritt's Tortuga Club. Both are timeshare resorts. There are also a few rental vacation homes in the area.
East End is quiet. There is nothing within walking distance of the two resorts, so a rental car is a must. Georgetown is about a 50 minute drive away except in rush hour. (Cayman has a
real rush hour traffic problem. Don't plan on a quick drive into Georgetown or 7 mile beach in the morning nor an easy exit from town in late afternoon.
There are three dive shops in East End operating a total of six dive boats.
Tortuga Divers is located at Morritt's Tortuga Club, and next door to The Royal Reef. CWB has given you links for Ocean Frontiers and Cayman Dive Lodge. All dive the same area around East End.
You can rent gear at any dive shop, but you may not
need a wetsuit. Water temperatures should be 82-84 degrees by June. I didn't wear a wetsuit last June at all. But, you may
want one. Early June is still thimble jellyfish season, and their larvae can cause itching and rashes in susceptible individuals.
In June, expect winds to be from the ESE on average. If the winds are moderate to brisk, the East End dive shops will be diving the north shore of East End. If the winds are light, dives could be anywhere, but all six EE boats will try to dive the four shallow sites just out front of Tortuga Divers. Those four sites are perhaps the best shallow sites on Grand Cayman. One, Snapper Hole, was ranked in the top ten for shallow dives in the entire Caribbean in a poll by Rodale's Scuba Diving magazine. This week we had the same divers request Snapper Hole three days running. Don't miss it!
Stingray City is the greatest diving/snorkling attraction on the island. It is an interaction experience with wild southern stingrays which have been hand fed for many years. There is a sandbar area which is quite shallow for snorkling with the rays, and diving is done a short distance away in 15ft depths.
If you want to avoid the crowds, plan your time in Georgetown for days when the cruise ship traffic is down. Check the scheduled cruise ship arrivals at
caymanport.com for the week of your stay. During the summer months, there are some days with no cruise ships. Bliss!
If you have any questions, feel free to ask me.