HoursThe Castillo de San Marcos is open to the public 7 days per week, except Thanksgiving Day (fourth Thursday in November) and Christmas Day (December 25). A maximum capacity of 100 visitors in the historic fort at any time will be in effect. First admission is at 9:00 a.m. and last admission is at 5:00 p.m. The Castillo closes and visitors must exit at 5:15 p.m. The park grounds are closed from midnight until 5:30 a.m.
