There are several dive shops on the island, take your pick. They will take you out for diving or snorkeling.
One place that we went was Mexico Rocks. It is a shallower area, 8-15 feet, and the water is quite clear teeming with beautiful fish.
Ambergris Caye has some of the best scuba diving in the world. This is a great place to go scuba while in Belize. The vis here is easily 50+ feet on a regular basis. I've never seen so many friendly rays and sharks in one spot my whole life.
We took all our dives with the shop at Ramon's Village. Even if you're not staying at the hotel I recommend going out with them. They have a great operation and equipment for rent.
Equipment: full rental equipment is available
For our second day of diving, our hotel booked us with Amigos Del Mar. These guys seem to do a lot more business than Ambergris Divers. They have a bigger shop, bigger dock, shaded picnic tables and in between dives, not only did we get watermelon and banana, we also got some coconut. But out on the water, there wasn't a whole lot of difference between the two dive operations except that our dive master at Amigos didn't appear to speak English as he did not speak a word to anyone and our captain gave the briefings.
We dove for 2 days while we were at Ambergris and our hotel booked us with a different dive operation each day. Our first day we dove with Ambergris Divers. They came to pick us up at our dock at Banana Beach Resort more or less on time. Our dive master and boat captain were young and very friendly. They had plenty of water on board and between dives they brought us back to their small dive shop for some water melon & bananas. We did two morning dives and two afternoon dives with Ambergris. By the fourth dive, me & Cliff were the only 2 divers left and the dive master asked us where we wanted to go. We had heard some people earlier talking about a tunnel dive, and we asked if we could do that. Despite the fact that it was a deep dive (70 ft max), and it is customary for safety's sake to dive shallower & shallower as the day progresses, our dive master agreed to take us to the tunnel as long as we kept an eye on the dive computer. The tunnel took about two minutes to get through, and it looked like there were more in the area after we emerged, but we had to get to shallower water, so we headed to the top of the reef in pretty short order and did some exploring. Even though we were pushing our limits for the day, I appreciated that our dive master bent the rules a little bit for us.
On the Hustler pier with Wet Willies is Hustler tours. Here you can rent a boat and a guide for a day of snorkeling or scuba at the reef or further afield like the Blue Hole.
Equipment: I brought my own snorkeling stuff but they have plenty of equipment to rent. I just like to have that perfect fit.
2nd largest reef in the world and the largest in the northern hemisfere. Fabulous ! Belize law states that you need to dive with a local divemaster.
The picture is not mine, please do not plagiarise it, thanks.
Equipment: We had our own equipement and got weights and tanks from the dive shop.
I did three dives including one night dive from Ambergris with CORAL BEACH HOTEL & DIVE CLUB. This operation was partly run from the hotel which is on the inside of Barrier street, and partly from the dive shop pier. The pier is the same one that Driftwood Dive shop uses on their snorkel trips.
Equipment: I brought my console and dive computer, mask, snorkel and fins, and they rented me tanks, weights and a BC at the dive shop. I was the only diver, and had a guide all to myself. I think now they mostly run live-aboard boats or cater to guests at the hotel.