Oct 15 - Dec 7Annual open enrollment
Jan 1 - Mar 31Advantage open enrollment
12 monthsTrial right for first-time Advantage
Part DNeeded to keep drug coverage
When you can switch
| Window | What you can do |
|---|---|
| Annual Enrollment, Oct 15 to Dec 7 | Return to Original Medicare, switch plans, or join a Part D plan. Changes start Jan 1 |
| Medicare Advantage Open Enrollment, Jan 1 to Mar 31 | If you are in an Advantage plan, you can switch to another plan or return to Original Medicare (and add a Part D plan) |
| Special Enrollment Period | Available after certain events, such as moving out of the plan's area or your plan leaving Medicare |
| 12-month trial right | If you joined Advantage when first eligible for Medicare, you can switch back to Original Medicare within the first 12 months |
Step by step
- Check the dates. Make sure you are within a window above.
- Join a stand-alone Part D plan if you want drug coverage. Original Medicare does not include it, and going without can lead to a late penalty.
- Apply for a Medigap policy first if you want one (see below). Do not cancel your Advantage plan until your new coverage is confirmed.
- Enroll in the new coverage. Joining Original Medicare with a Part D plan generally ends your Advantage plan, but confirm with your plan or 1-800-MEDICARE.
The Medigap catch
Medigap insurers generally must sell you a policy without health questions only during your 6-month Medigap open enrollment period after you turn 65 and enroll in Part B. If you leave Advantage later, in most states the insurer can use medical underwriting, which means they can decline you or charge more. A few states, including New York and Connecticut, give broader guaranteed access. Check your state before you switch.
Your 12-month trial right is the exception: if you joined Advantage when first eligible and leave within 12 months, you have a guaranteed right to buy certain Medigap plans.
Compare the full cost. Original Medicare plus Medigap and Part D can cost more each month but may cost less in a bad year. Add up premiums, the $283 Part B deductible, and what the plan covers before you decide.
Considering the other direction? See Medicare Advantage in 2026 and open enrollment.