The submarine pen appears to serve as storage and shelter for equipment and boats. It consists of three entrances, the north-most of which may serve as a spawn point for the Launch. Several exterior docking points around the base also serve as spawn locations for the Reefer.
A large courtyard at the southern quarter of the base as it merges with the main road creates a triangular section where a Hunter may spawn after all-Gold completions of Flight School. Behind the main base, a Barracks can spawn, and a military-styled Patriot can spawn near the LHD.
Like Area 69, Easter Basin Naval Station is a restricted area. The player will be granted a 5-star wanted level upon entry, be it on-foot, inside any type of vehicle, or flying low above the site. The LHD features surface-to-air missiles, however these are only used during the mission Vertical Bird, and are disabled outside of this mission.
The base has defined pedestrian paths, allowing police officers to spawn in the base when the player is wanted. Military officers will not spawn, as they are not able to spawn on foot in paths. On rare occurrences, civilian pedestrians, including prostitutes, may walk into the base from nearby streets.
Easter Basin Naval Station appears to be based on the former Hunter's Point Naval Shipyard in San Francisco.
Events of Grand Theft Auto: San Andreas
The base is featured during the mission Vertical Bird, in which government agent Mike Toreno orders CJ to sneak in LHD-069 and steal a Hydra from it. Carl enters the ship through its rear bay, then flies away in a Hydra which he uses to destroy Tropics in the Sherman Reservoir, before safely landing the aircraft at Verdant Meadows. This is the only time the LHD-069's S.A.M. sites are active, although they can be disabled from a control room within the ship.
- One snapshot - above the mounted SAM site. This can be safely taken from distance from a boat.
- Two oysters. These oysters are the most difficult to obtain because the player will instantly get a 5-star wanted level when trespassing within the base's perimeter, though sometimes it will drop to 4 stars if fleeing the base by boat:
- One in front of the LHD
- One in the middle tunnel of the sub pen
It is best to collect these oysters during Vertical Bird before reaching the back of the LHD, as the wanted level is deactivated for the mission. The mission The Da Nang Thang also allows exploration right after the helicopter was taken down. If not, it is recommended to use a speedboat for a quick getaway then escape east, go upstream and save at Mike Toreno's Ranch or the Fort Carson Safehouse. Alternatively, park the boat near the NRG-500 in the docks area and make a run for the Doherty Safehouse with the NRG-500 via the railway line. This will fail the repeatable NRG-500 Challenge but the upside is that the cops near the player despawn when the challenge starts.
- A helipad appears marked on the map, despite not being present.
- There is a sign at the entrance that says "Unauthorized persons will be shot at". The sign is, indeed, true to its word, as when the player gains a five-star wanted level upon entry or flying over the base, police officers that spawn within the base will shoot at the player as well as being shot by pursuing Police Mavericks and if flying on an aircraft, enemy Hydras will try to shoot down the player's aircraft.