ST. AUGUSTINE, Fla., Oct. 25, 2026 — Built by the Spanish to defend Florida and the Atlantic trade route, Castillo de San Marcos National Monument "preserves the oldest masonry fortification in the continental United States," according to the National Park Service. The site interprets "more than 450 years of cultural intersections," the agency says (NPS).

What you'll see

The NPS says a drawbridge over a dry moat "was the only way into the Castillo" (NPS). In the water battery on the fort's east side, a furnace once heated cannonballs "red hot to be fired at wooden vessels" (NPS). The fort displays both iron and bronze cannon and mortar from the period (NPS).

For many families, the highlight is the noise. The NPS says cannon firing demonstrations are scheduled five times a day every Friday, Saturday and Sunday (NPS).

What it costs

  • Adults 16 and older: $15, valid for seven consecutive days (NPS fees)
  • Children 15 and under: free, with an adult (NPS fees)
  • Castillo Annual Pass: $45, covering the passholder and three additional adults (NPS fees)

The park "does not accept cash," so only credit and debit cards work (NPS fees). Holders of America the Beautiful passes, including the free pass for U.S. fourth graders, get in under the pass terms (NPS fees).

Fee-free day: The NPS lists Nov. 11, Veterans Day, as a 2026 entrance fee-free date for U.S. citizens and residents (NPS fees). The same list includes Oct. 27, Theodore Roosevelt's birthday (NPS fees).

When to go

The Castillo is open seven days a week except Thanksgiving and Christmas Day, according to the NPS hours page. First admission is 9 a.m. and last admission is 5 p.m.; visitors must exit by 5:15 p.m. (NPS hours).

Timing matters. The NPS says visitation "is lowest from mid-September through mid-November" and highest around holidays, especially Christmas to New Year's (NPS hours). A busy Saturday averages 3,500 visitors (NPS hours). School group visits are high in October and November (NPS hours).

Fall and spring are the mildest seasons, when temperatures regularly hover around 70 to 80 degrees, the agency says (NPS hours). During thunderstorms, the gun deck closes because of lightning danger (NPS hours). The NPS says there are no refunds for weather closures of the upper level, though lower interior rooms stay open (NPS fees).

Parking

The City of St. Augustine runs a lot in front of the Castillo that costs $2.50 per hour, according to the NPS (NPS fees). The agency suggests the city's parking garage a block away as a shaded option (NPS fees). Vehicles longer than 21 feet, including trailers, can't use the Castillo lot. The city offers free parking for larger vehicles at West Castillo Drive and Riberia Street (NPS fees).

Address: 1 South Castillo Drive, St. Augustine. Phone: 904-829-6506 (NPS).

Sources

  1. National Park Service, Castillo de San Marcos National Monument: https://www.nps.gov/casa/index.htm
  2. National Park Service, "Fees & Passes": https://www.nps.gov/casa/planyourvisit/fees.htm
  3. National Park Service, "Operating Hours & Seasons": https://www.nps.gov/casa/planyourvisit/hours.htm

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