Roatán, located between the islands of Útila and Guanaja, is the largest of Honduras' Bay Islands. The island was formerly known as Ruatan and Rattan. It is approximately 60 kilometres (37 mi) long, and less than 8 kilometres (5.0 mi) wide at its widest point.

The island consists of two municipalities (out of a total of four in the department): Jose Santos Guardiola in the east (named for the former president of Honduras) and Roatán (also including the Cayos Cochinos) further south in the west. The most populous town of the island is Coxen Hole, capital of Roatán municipality, located in the southwest. Other important towns include French Harbour, West End, and Oak Ridge, the capital of Jose Santos Guardiola municipality.

The easternmost quarter of the island is separated by a convoluted channel through the mangroves that is 15 meters wide on the average. This section is called Helene, or Santa Elena in Spanish. Satellite islands at the eastern end are Morat, Barbaretta, and Pigeon Cay. Further west between French Harbour and Coxen Hole is Barefoot Cay. Known as Burial Key until 2001, Barefoot Cay now is privately owned and houses a luxury resort popular with celebrities.

Located near the Mesoamerican Barrier Reef, the largest barrier reef in the Caribbean Sea (second largest worldwide after Australia's Great Barrier Reef), Roatán has become an important cruise ship and scuba diving destination in Honduras. Tourism is its most important economic sector, though fishing is also an important source of income for islanders.