Mare Island Federal Credit Union was founded in 1936, during the inter-war period to serve the ship builders of Mare Island. Over the years it has merged with many other financial institutions in the North Bay Area Napa Postal Federal Credit Union (1999); Electrical Workers Local 180 FCU (2002); Vallejo Schools Employees FCU (2005); Vaca Valley FCU (2007; and Embarcadero Financial FCU, United Medical FCU, St. Francis Memorial Hospital FCU, Franklin Employees FCU (2009).
In the early 1970s the credit union decided to open a small branch in Vallejo to increase access for members who did not live on Mare Island. When the Navy decided to close the shipyard in 1996, the credit union had to change its model as the entire member base was no longer employed on Mare Island.
In 1996 it was renamed 1st Pacific Federal Credit Union, and in 1999 was renamed 1st Pacific Credit Union. And, finally, in 2011, 1st Pacific Credit Union joined the Self-Help Federal Credit Union family, with branches still serving the communities of Napa and Vallejo, California.