Mayport Naval Station is just bursting with local military history. If this interests you, find out about any group tours and one-off happenings.
You'll have no end of sightseeing choices when in Beach Cities. Mayport Naval Station is an ideal place to start here, but there are loads of other worthy attractions to experience. Kathryn Abbey Hanna Park, Timucuan Ecological & Historical Preserve, and Atlantic Village Shopping Center are not far from the military installation and will top off your day nicely.