It's free but you have to pass a security check at the East gate
Can you bring water in with you?
Free admission, for the security clearance you will need current identification and proof of vehicle insurance to enter the Naval Yard.
No admission, and cold war museum. Is also good museum.
AJ is right, no admission fee but security check at the Navy Yard main gate. Also remember that there is a second building (Cold War and newer) and a lot of outdoor exhibits like a huge rail mounted shore gun.
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