Dates when the Military Services Switched Over from Service Numbers to Social Security Numbers:
| Service | Date Switched Over |
| Army and Air Force | July 1, 1969 |
| Navy and Marine Corps | January 1, 1972 |
| Coast Guard | October 1, 1974 |
Explore US Military
Dates when the Military Services Switched Over from Service Numbers to Social Security Numbers:
| Service | Date Switched Over |
| Army and Air Force | July 1, 1969 |
| Navy and Marine Corps | January 1, 1972 |
| Coast Guard | October 1, 1974 |