Harry Sit at The Finance Buff explains on how to join Navy Federal Credit Union without military affiliation. By joining Navy Federal Credit Union, the largest credit union in the U.S, you can benefit from its great rates on CDs and loans. The first step is to become a member of the Navy League, a non-profit organization that supports America’s sea services, by paying $25 tax-deductible membership fee online. (thefinancebuff.com)