Enrollment periods
Medicare Enrollment Periods and Key Dates
Medicare has set times when you can sign up for coverage or make changes. Knowing them helps you avoid gaps in coverage and late penalties.
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Around your 65th birthday
Initial Enrollment Period
A 7-month window: the 3 months before the month you turn 65, your birthday month, and the 3 months after.
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October 15 – December 7
Annual Enrollment Period
Join, switch or drop a Medicare Advantage or Part D plan. Changes take effect January 1.
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January 1 – March 31
Medicare Advantage Open Enrollment
If you’re in a Medicare Advantage plan, you can make one switch to another Medicare Advantage plan or go back to Original Medicare.
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Throughout the year
Special Enrollment Periods
Certain life events, like moving or losing other coverage, may let you make changes at other times.
What can I change, and when?
| Period | Dates | What you can do |
|---|---|---|
| Initial Enrollment Period | 7 months around your 65th birthday | Sign up for Parts A and B, and join a Medicare Advantage or Part D plan |
| Annual Enrollment Period | October 15 – December 7 | Join, switch or drop a Medicare Advantage or Part D plan; switch between Original Medicare and Medicare Advantage |
| Medicare Advantage Open Enrollment | January 1 – March 31 | If you’re in Medicare Advantage: switch to another Medicare Advantage plan, or return to Original Medicare and join a Part D plan (one change) |
| General Enrollment Period | January 1 – March 31 | Sign up for Part A and/or Part B if you missed your Initial Enrollment Period; coverage starts the month after you sign up |
| Medigap Open Enrollment Period | 6 months, starting when you’re 65+ and have Part B | Buy a Medicare Supplement policy without health questions |
| Special Enrollment Periods | Varies | Make changes after certain life events |
Examples of Special Enrollment Periods
- You move to a new address that’s outside your plan’s service area
- You lose job-based or other health coverage
- You move into or out of a nursing home or other institution
- You qualify for Medicaid or Extra Help
- Your plan changes its contract with Medicare
Rules and timing differ for each situation. A licensed insurance agent can help you understand whether you may qualify.
Reviewed October 2026. Medicare rules and costs change every year. For the latest official information, visit Medicare.gov or call 1-800-MEDICARE (TTY 1-877-486-2048).
Questions about Medicare? Talk with a licensed agent.
Mon–Fri, 8 a.m.–6 p.m. ET · TTY: +1 877-486-2048