Medicare Enrollment Periods: When You Can Sign Up or Switch
Medicare has fixed windows for signing up and for changing plans. Miss one and you may wait months for coverage or pay a penalty for life. Here is every period, in plain terms.
| Period | When | What you can do |
|---|---|---|
| Initial Enrollment Period | 3 months before the month you turn 65, that month, and 3 months after | Sign up for Part A and Part B, and join a Medicare Advantage or Part D plan. Signing up before your birthday month means coverage starts on time. |
| Open Enrollment (Annual Enrollment Period) | October 15 to December 7, 2026 | Switch between Original Medicare and Medicare Advantage, change Advantage plans, or join, switch or drop Part D. Changes start January 1. |
| Medicare Advantage Open Enrollment | January 1 to March 31 | If you’re in a Medicare Advantage plan, make one switch to another Advantage plan or go back to Original Medicare (and join a Part D plan). |
| General Enrollment Period | January 1 to March 31 | Sign up for Part A or Part B if you missed your initial window and don’t qualify for a special period. Coverage starts the month after you sign up, and late penalties may apply. |
| Special Enrollment Periods | Varies | After certain events: losing job-based coverage (8 months for Part B), moving out of your plan’s area, qualifying for Extra Help or Medicaid, and others. |
| Medigap Open Enrollment | 6 months, starting the month you’re 65 or older and have Part B | Buy any Medigap policy sold in your state without medical questions. After it ends, insurers in most states can turn you down or charge more. |
The window most people regret missing: Medigap Open Enrollment. It happens once, and it doesn’t repeat when you leave a Medicare Advantage plan later (apart from limited trial rights). If you might want Original Medicare plus Medigap, decide during this window.
Questions
When is Medicare open enrollment for 2027?
October 15 to December 7, 2026. Changes you make take effect January 1, 2027.
Can I change Medicare plans after December 7?
If you’re in a Medicare Advantage plan, you can make one change from January 1 to March 31. Otherwise you generally need a Special Enrollment Period.
Do I have to sign up for Medicare at 65 if I’m still working?
Not always. If you have coverage from a group health plan based on your or your spouse’s current job, you can usually delay Part B without a penalty and sign up within 8 months of that coverage or job ending. Check whether your employer plan requires Medicare to pay first (common at employers with fewer than 20 employees).
Sources
Official sources only, checked October 17, 2026.
- Medicare.gov, “When can I join a health or drug plan?” — medicare.gov.
- Medicare.gov, “When does Medicare coverage start?” — medicare.gov.
- CMS and NAIC, “Choosing a Medigap Policy” (March 2026), Medigap Open Enrollment — medicare.gov.
Educational information, not medical, legal or financial advice. We are not connected with or endorsed by the U.S. government or the federal Medicare program. · Advertiser disclosure