10 U.S.C. § 8326: Enlisted members: 30 years

Each enlisted member of the Regular Navy or the Regular Marine Corps who applies for retirement after completing 30 or more years of active service in the armed forces shall be retired by the President. For the purpose of subsection (a), “enlisted member” includes a member of the Regular Navy or the Regular Marine Corps who holds a permanent enlisted grade and a temporary appointment in a commissioned or warrant officer grade. unless otherwise entitled to a higher grade, shall be retired in the grade in which serving at the time of retirement; and unless otherwise entitled to higher pay, is entitled to retired pay computed under section 8333 of this title .