Bahía de la Ascensión, Protected bay in Quintana Roo, Mexico.

Bahía de la Ascensión is a shallow bay on the western Caribbean coast of Quintana Roo, Mexico. Its low, mangrove-covered shores enclose a broad expanse of water, and Cayo Culebra, the only significant island, lies in the middle of its mouth. Because of its low depth, large ships cannot navigate it, so it has no deep-water port.

Spanish explorer Juan de Grijalva reached the bay in 1518 during the Christian feast of Ascension, an encounter that determined its current name. Over the following centuries, it served as an anchor point for navigation and fishing along this coastline.

The bay's name comes from the feast of the Ascension, the religious holiday on which Juan de Grijalva arrived in 1518. In the early years of the Quintana Roo Territory, a small port at Vigía Chico linked the bay by railway to Santa Cruz de Bravo, today Felipe Carrillo Puerto.

The shallow depth prevents large vessels from entering, so visitors rely on small boats and kayaks to explore the bay. Access is regulated as part of the Sian Ka'an Biosphere Reserve, and timing your visit according to local conditions helps with navigation and wildlife viewing.

The bay's only significant island, Cayo Culebra, sits at the center of its mouth where it meets the Caribbean Sea. The bay was named by Juan de Grijalva in 1518 after the feast of the Ascension, the religious holiday on which he sighted it.