Turneffe islands, Marine reserve atoll in Belize District, Belize.

Turneffe Atoll lies 32 km off Belize City and runs about 48 km long and 16 km wide, the largest coral atoll in Belize and in the Mesoamerican Barrier Reef System. Its flats, creeks and lagoons hold more than 150 mangrove islands and higher cayes with savanna and littoral forest. Mauger Caye, at the northern end, carries a lighthouse; a smaller aid to navigation stands on Caye Bokel in the south.

In the winter of 1717–1718 the pirate Blackbeard, Edward Teach, used Turneffe while raiding shipping between Vera Cruz and the Bay of Honduras. On 4–5 April 1718 he captured the ten-gun logwood sloop Adventure here, forced its captain David Herriot to join him and gave the vessel to Israel Hands. The atoll became a marine reserve on 22 November 2012, co-managed since October 2013 by the Turneffe Atoll Sustainability Association.

The atoll's name comes from the Spanish word for the three flat cays that make up its northern group. Fishing and diving are the main activities around the islands, and the shallow flats, creeks and lagoon are used for catching lobster, conch and fish. The reserve is co-managed by the Turneffe Atoll Sustainability Association, appointed in October 2013.

Boats leave from Belize City, about 32 km (20 miles) away; the crossing depends on sea and weather conditions. The atoll is a marine reserve co-managed by the Turneffe Atoll Sustainability Association, so fishing and collecting are restricted. Bring sun protection and fresh water, as the cayes have little shade and few facilities.

At the northern end of the island group stands Mauger Caye, whose lighthouse marks the atoll's main aid to navigation; a smaller light sits at the southern end on Caye Bokel. Between 4 and 5 April 1718 Blackbeard took the ten-gun logwood sloop Adventure here and forced its captain, David Herriot, into his crew.