# Medicare Enrollment Periods (IEP, AEP, OEP, SEP)

There are several Medicare enrollment periods, and missing the right one can cost you a lifetime penalty or a coverage gap. The main ones are the Initial Enrollment Period (IEP) around your 65th birthday, the Annual Election Period (AEP) each fall, the Medicare Advantage Open Enrollment Period, the General Enrollment Period, and Special Enrollment Periods.

## What it means

- Initial Enrollment Period (IEP): 7 months — 3 months before, the month of, and 3 months after you turn 65.
- Annual Election Period (AEP): October 15 – December 7 each year, when you can join, drop, or switch a Medicare Advantage or Part D plan for coverage starting January 1.
- Medicare Advantage Open Enrollment Period (MA OEP): January 1 – March 31, when you can switch Advantage plans once or return to Original Medicare.
- General Enrollment Period (GEP): January 1 – March 31 for people who missed their Initial Enrollment Period.
- Special Enrollment Periods (SEPs) are triggered by qualifying events like losing employer coverage, moving, or qualifying for Extra Help.

## Action steps

1. Mark your 65th birthday month on the calendar and count back 3 months — that's when your Initial Enrollment Period begins.
2. If you're already 65 and have employer coverage, ask your HR department whether that coverage is 'creditable' for Part D.
3. Set a reminder for October 15 every year to review your Advantage/Part D plan during AEP.
4. If you experience a qualifying life event (moving, losing coverage), check medicare.gov for the SEP that applies.

## Deadlines

- IEP: 7 months around your 65th birthday.
- AEP: October 15 – December 7 each year.
- MA OEP: January 1 – March 31.
- GEP: January 1 – March 31.

## Questions

### What are the AEP dates?

The Annual Election Period runs October 15 through December 7 each year. Changes take effect January 1.

## Sources

- [When to sign up for Medicare (medicare.gov)](https://www.medicare.gov/basics/get-started-with-medicare/sign-up/when-does-medicare-coverage-start)
- [Joining a Medicare plan (medicare.gov)](https://www.medicare.gov/basics/get-started-with-medicare/sign-up/joining-a-plan)

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Canonical: https://seniordirectanswers.com/library/enrollment-periods
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Published: 2026-07-18T00:00:00+00:00
Modified: 2026-07-18T00:00:00+00:00
Last verified: 2026-07-18
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