At 25 miles (40 km) long and 4½ miles (7 km) wide at its widest point, Ambergris is the queen of the cayes. On early maps it was often referred to as Costa de Ambar, or the Amber Coast, a name supposedly derived from the blackish substance secreted by sperm whales—ambergris—that washes up on the beaches. Having never seen any ambergris in Belize, or a sperm whale, we’re not sure we buy this explanation.
Here the reef is just a few hundred yards from shore, making access to dive sites extremely easy: the journey by boat takes as little as 10 minutes. Because Ambergris Caye is by far Belize’s largest island and was the first to cater to those hoping to witness Belize's undersea world, it's generally superior in the number of dive shops, experience of dive masters, and range of equipment and facilities it offers. San Pedro has Belize's only hyperbaric chamber and an on-site doctor to tend to divers with the bends. Many dive shops are attached to hotels, where the quality of dive masters, equipment, and facilities can vary considerably.
But there's more than diving to Ambergris Caye. Today the majority of visitors to the island don't dive at all. They snorkel, fish, splash in the sea, go sailboarding, or just laze around the hotel pool until it's time to sample one of the dozens of restaurants on the island. With an island population of around 20,000, according to local observers who point to the many mainlanders who have come to the island to find work and to foreign expats who spent part of the year on the caye, or 11,510, according to the 2010 Belize Census, Ambergris and its only real town, San Pedro, remain friendly and prosperous. The caye has one of the country's highest literacy rates and an admirable level of awareness about the reef's fragility.