Ambergris Caye, or Cayo Ambergris, is the largest island in Belize and part of the country's Cays. It measures 40 km (25 mi) and is only separated from the mainland of Mexico by a narrow stretch of water on its northern side.

The Belize Barrier Reef runs parallel with the northern part of the island's eastern coast. The reef is a UNESCO world heritage site.

Archaeological evidence shows that Mayan people have lived on the island for thousands of years. At several locations on the Ambergris Caye, distinctive polished red ceramics have been unearthed to corroborate that. After the arrival of the Spanish, the indigenous population dwindled.

The main town on Ambergris is San Pedro and east of town, about 1 km (0.6 mi) off the coast lies a beautiful reef. In San Pedro, trips and excursions to diving and snorkeling spots, as well as to other cays in the region are widely available.

There are several holiday resorts, but otherwise it has a laid-back atmosphere. Ambergris Caye boasts numerous beautiful beaches.

The center of the island is largely untouched and features white coral sand and mangrove forests.

Accommodation on Ambergris Caye is available in San Pedro, as well as in several holiday resorts that are scattered over the cay. Ambergris Caye has a population of only about 2,000.

The cay is located 60 km northeast of Belize City and 120 km northeast of Belmopan.