Glossary
General Enrollment Period (GEP)
The Jan 1 – Mar 31 window each year when you can sign up for Medicare if you missed your Initial Enrollment Period.
What is it?
The General Enrollment Period runs January 1 through March 31 every year. It's the fallback for anyone who missed their IEP and doesn't qualify for a Special Enrollment Period. Coverage starts the first of the month after you enroll.
Why does it matter?
If you missed IEP, GEP is your only way back in — but you'll likely owe the Part B late-enrollment penalty for life.
When you'll encounter it
Only if you missed your IEP window.
Impact on Medicare
Coverage begins the month after you enroll, not retroactively.
Impact on TRICARE For Life
TFL stays inactive until both Parts A and B are effective. Any gap means paying full cost for civilian care.
Common misconceptions
- "GEP coverage is retroactive." — It is not. There can be a multi-month gap between GEP signup and coverage start.
Related glossary terms
Official sources
Last reviewed January 2026 against the 2026 Medicare & You and TRICARE For Life handbooks.