East of Jacksonville, at the mouth of the St. Johns River, Hwy-A1A curves around a large U.S. Navy base (third largest in the country, specializing in helicopters, which you’ll often see hovering overhead), past the busy Bath Iron Works shipyard and the sizable fishing port of Mayport, where you can enjoy a quick bite at Singleton’s Seafood Shack (4728 Ocean St., 904/246-4442), about 170 yards west of the ferry landing. From Mayport, Hwy-A1A zigzags inland south and east, reaching the water again at Jacksonville Beach, a welcoming, family-oriented community with the usual gauntlet of cafés, mini-golf courses, and video arcades, and a nice beachfront centering on a small pier.
South of Jacksonville Beach spreads the enclave of Ponte Vedra Beach, where country club resorts replace roadside sprawl. Hwy-A1A bends inland through here, so if you want to keep close to the shore (most of which is private), follow Hwy-203 instead, rejoining Hwy-A1A on the edge of town.
South of Ponte Vedra, Hwy-A1A passes a pair of beachfront state parks: the marvelous 9,815-acre Guana River and smaller South Ponte Vedra, both of which give access to usually uncrowded sands.