Area code 721 is the telephone area code in the North American Numbering Plan (NANP) for Sint Maarten, a constituent country of the Kingdom of the Netherlands in the Caribbean.
Previously, Sint Maarten used the country code 599, originally assigned to the now-dissolved Netherlands Antilles, and still in use by Curaçao and the Caribbean Netherlands (Bonaire, Sint Eustatius, and Saba).
The northern French side of the island, known as Saint-Martin, does not use the North American Numbering Plan, and has the country code +590, shared with Guadeloupe and Saint Barthélemy.
On July 27, 2011, the North American Numbering Plan Administrator (NANPA) granted the issuance of the area code to Sint Maarten.
Call within the country are established with seven-digit dialing of the local telephone number.