The hook
The US Navy's first Pacific shipyard — 142 years of warships, from wooden paddle steamers to nuclear submarines — sits half-preserved, half-reborn across the strait from Vallejo, with a chapel full of Tiffany windows.
01Why it's worth it
Mare Island built more than 500 ships between 1854 and its 1996 closure, and walking it now is the Bay Area's best industrial time capsule: colossal dry docks of quarried granite, crane rails, ammunition bunkers, officers' mansions on a eucalyptus-lined avenue, and the shipyard museum run by veterans who worked the yard and will talk submarines as long as you'll listen. The unexpected treasure is St Peter's Chapel (1901), the oldest naval chapel in the country, whose interior glows with one of the largest collections of Tiffany stained-glass windows anywhere — a jewel box nobody expects on a shipyard. The island today is mid-rebirth — breweries and a coal-shed distillery in the old machine shops, film crews in the derelict blocks — which gives it a working, unpolished feel no curated museum district has. It's also a hinge of harder history: the WWII boom here and at Port Chicago shaped (and segregated) the East Bay's Black working class, a story the museum handles directly.
02How to experience it
Cross the causeway from Vallejo (ferry from SF to Vallejo makes it car-optional). Do the museum first for orientation, time St Peter's Chapel's open hours (limited — check ahead), then wander Officers' Row and the waterfront dry docks. Finish at the Mare Island Brewing Co. taproom in the old coal sheds. Some historic buildings are accessible only on the museum's walking tours — worth planning around.