The small islet was a sanctuary dedicated to Tezcatlipoca before the Conquest, and in 1518 it was discovered by Juan de Grijalva.

The construction of the fortress was planned since Hernán Cortés' arrival in 1519 to defend the port from constant pirate attacks, and in 1554 its construction began using coral stone from the area.

Over time, it became one of the most important fortresses of its time.

In 1568, it witnessed the Battle of San Juan de Ulúa, where a fleet of the Spanish Armada fought against English privateers led by Francis Drake.

In 1683, it suffered severe damage from an attack by the pirate Lorencillo and was rebuilt in 1692.

The historic fortress served as the last Spanish refuge during the War of Independence, which led to it being used to attack the city instead of defending it from 1823 to 1825. It defended Veracruz against repeated attacks from French and American armies.

In the second half of the 19th century, it was used as a prison, just as it was during the colonial period. Several notable figures from Mexican history were imprisoned in these cells, including Benito Juárez and Fray Servando Teresa de Mier. Jesús Arriaga, known as Chucho el Roto, a famous thief who helped the poor and managed to escape from the fortress walls, was also held here.

The fort has become one of the representative landmarks of the city due to its rich history.

Currently, the moat, ramp, five bastions, and some dungeons are preserved and have been adapted to house a museum exhibition that explains the history and development of the building using models and drawings.

The museum displays some artifacts from the colonial period and relics related to its various battles.

Of note is the room that narrates the history of pirate attacks suffered by the port of Veracruz, with period weaponry and ship models.

During the visit to San Juan de Ulúa, you can also see Mexico's first lighthouse by crossing the "Bridge of the Last Breath."

Additionally, the guide may want to tell the legend of La Mulata de Córdoba, who is said to have been imprisoned here by orders of the Spanish Inquisition and painted a ship on the walls of her cell from which she managed to escape.