Castillo de San Marcos
The Castillo de San Marcos, started in 1672, is the oldest masonry fort in the country. It has been owned by four different governments and is now a national park. It was not retired as a fort until 1933; that's 251 years of service. It is in remarkably good shape for its advanced age, and reflects the Spanish roots of St. Augustine.
Black Raven Pirate Ship
Now for something completely different, the Black Raven Pirate Ship is fun for all ages. See a live interactive performance while cruising Matanzas Bay and fight off the Queen Anne's Revenge and get the treasure. There is a bar and a gift shop on board. There are adult only tours with racier material as well. The Black Raven docks in downtown St. Augustine.
Colonial Spanish Quarter
In the oldest city in the USA, it seems fitting to explore the history of the area, and it can be found in the Colonial Spanish Quarter and its museum. Kids get to make their own toys at the museum and the "residents" of the quarter are dressed and working as if it were 1740. They will talk about life in 1740 and their roles as soldiers, their wives and other citizens. The Taberna de Gallo, or tavern of the rooster, is open a few nights a week and is an authentic tavern of the time, but with good drinks. Visitors can buy items made in the village that would have been used in 1740.
El Conquistador Speedboat
After experiencing the slower moving time period of the 18th century, gear up for a very fast ride on El Conquistador Speedboat! Schedule a 30-minute thrill ride or a 60-minute ride and tour of waterfront points in St. Augustine. This boat docks downtown as well. Riders will get wet, so wear clothes that can take it.
St. Augustine Alligator Farm
Zip-line over the alligators at St. Augustine Alligator Farm, begun in 1893! There are also toucans and boa constrictors here and 23 species of alligators. Other exotic birds and crocodiles also inhabit the Farm and visitors learn about them as they tour. The alligator feeding might be the most interesting part, and it is a kind of learning even if it is a bit unsettling.
The beach is one of the best attractions in St. Augustine because it's in Florida. Water sports galore are available in many places near the beaches, of course, with rentals of all water-related activities. The temperature is usually accommodating.