2026–2027 Medicare Enrollment Periods: When Can You Switch?
Bottom Line
You can generally switch Medicare Advantage or Part D plans during fall Open Enrollment; other windows depend on your enrollment or qualifying events. Fall changes start January 1, but don't automatically give you Medigap access without underwriting.
You can switch Medicare Advantage or Part D drug plans only during specific enrollment windows: your Initial Enrollment Period when you first become eligible, the annual Open Enrollment Period from October 15 to December 7, the Medicare Advantage Open Enrollment Period from January 1 to March 31 (if you already have an Advantage plan), or a Special Enrollment Period triggered by a qualifying life event. Outside those windows, you generally have to wait. Medigap (Medicare Supplement) rights follow a different set of rules entirely — the annual open enrollment period does not automatically give you a guaranteed right to buy a new Medigap policy without medical underwriting.
Knowing which window applies to your situation is the whole game, because the deadlines are firm and the coverage effective dates differ. This page walks through each period, what changes it allows, and how Medigap fits in. And because many people review all their insurance at once: if you are also looking at permanent life insurance for your family or estate, comparing guaranteed universal life rates is a separate coverage and budgeting decision — it is not a Medicare product or part of any Medicare enrollment, so keep the two conversations distinct.
Initial Enrollment Period: Your First Chance to Choose
Your Initial Enrollment Period (IEP) starts three months before the month you get Medicare Part A and/or Part B and ends three months after that month, according to Medicare.gov’s joining-a-plan guidance. During the IEP you can join any Medicare Advantage plan (you need both Part A and Part B) or any Part D drug plan (you need either Part A or Part B).
Timing matters for when coverage starts:
- If you join before your Part A and/or Part B starts, plan coverage begins the same day your Medicare starts.
- If you join after your Medicare starts, coverage begins the first of the month after the plan receives your request.
If your Part A already started and you are adding Part B later, a separate IEP for new Part B enrollees gives you two months after you first have both parts to join a plan, with coverage starting the month after you join.
If you are preparing for this first decision, it helps to review what getting ready to enroll in Medicare involves — the paperwork, your Medicare card details, and the coverage information plans will ask for — before your window opens.
Annual Open Enrollment (October 15 – December 7)
This is the main switching window each year, and it applies to almost everyone with Medicare. Per Medicare.gov’s Open Enrollment page, between October 15 and December 7 you can:
- Join, drop, or switch to another Medicare Advantage plan, with or without drug coverage.
- Switch from Original Medicare to a Medicare Advantage plan, or from an Advantage plan back to Original Medicare.
- Join, drop, or switch a standalone Part D drug plan if you are in Original Medicare.
Changes take effect January 1 of the next year, and the plan must receive your enrollment request by December 7.
The Medigap trap. If you switch from a Medicare Advantage plan back to Original Medicare during this window, you may want a Medigap policy to help pay your share of costs — but Medicare.gov notes there are limits on when you can add it. Open Enrollment itself is not a guaranteed-issue right for Medigap in most cases. Outside your six-month Medigap Open Enrollment Period (which starts the month you are 65 and enrolled in Part B), an insurer can require medical underwriting and can decline or rate you. Medicare.gov’s Medigap switching page stresses that these are federal rights and that some states offer more opportunities — check your State Insurance Department. If you already have Medigap and are thinking about joining an Advantage plan, understand what happens to Medigap when you choose Advantage before you cancel anything: in most cases a dropped policy cannot be recovered, and your future ability to return to a supplement may depend on underwriting or limited trial-period rights.
Medicare Advantage Open Enrollment (January 1 – March 31)
This window is only for people already in a Medicare Advantage plan. From January 1 through March 31, you can:
- Switch to a different Medicare Advantage plan, with or without drug coverage.
- Drop your Advantage plan and return to Original Medicare, and join a separate Part D drug plan.
Coverage starts the first of the month after the plan receives your request. There is also a first-three-months rule: if you joined an Advantage plan when you first got Medicare, you can switch plans or return to Original Medicare within your first three months of having both Part A and Part B.
Special Enrollment Periods: Switching Outside the Calendar
Special Enrollment Periods (SEPs) exist for specific life events, and the window length depends on the event. The most common ones, documented on Medicare.gov’s Special Enrollment Periods page, include:
| Life event | Typical window |
|---|---|
| Move out of your plan’s service area (or new plan options at a new address) | Begins when you move (or the month before, if you notify your plan in advance) and lasts 2 full months after the move |
| Lose employer or union coverage (including COBRA) | 2 full months after the month coverage ends |
| Lose Medicaid eligibility or Extra Help | 3 full months from the date you lose eligibility or are notified, whichever is later |
| Have Medicare and Medicaid, or get Extra Help | Can change drug coverage once per calendar month |
| Move back to the U.S. from abroad | 2 full months after the month you return |
| Plan contract with Medicare ends (plan termination) | Varies — generally starts 1–2 months before the contract ends and ends 1–2 full months after, depending on how the contract ends |
| Plan contract not renewed | December 8 through the last day of February of the following year |
Other SEPs cover 5-star plan switches (usable once between December 8 and November 30 the following year), significant provider network changes, plan sanctions or state receivership, incarceration release, and exceptional circumstances such as enrolling based on misleading information. If your situation is unusual, call 1-800-MEDICARE to confirm whether an SEP applies.
If your plan is being discontinued, that is different from an ordinary annual benefit change — a termination gives you a defined replacement window and, if you do nothing, you fall back to Original Medicare. Before acting on that notice, review the rules for replacing a discontinued Medicare Advantage plan and verify your specific deadlines and rights in the letter your plan sends, because the SEP length depends on exactly how the contract ended.
Part D Switching Rules in Brief
Drug coverage follows the same calendar: switch during Open Enrollment for a January 1 effective date, or use the Advantage Open Enrollment Period if you have an Advantage plan with drug coverage. When you switch drug plans, your old coverage ends when the new coverage begins — you do not need to cancel the old plan separately, per Medicare.gov’s drug-plan switching page. One caution: if you go 63 days or more in a row without other creditable drug coverage, you may face a late enrollment penalty when you rejoin.
How to Decide Whether to Switch
Enrollment periods tell you when you can change; they do not tell you whether you should. Before any window closes:
- List what changed. Premium, deductible, drug costs, doctor or hospital network changes, or a plan’s star rating.
- Check networks directly. Ask your doctors and pharmacies whether they participate in each plan you are considering.
- Run your drugs through each plan. Use Medicare.gov’s plan comparison tools to estimate total annual drug cost per plan, not just the premium.
- Confirm your Medigap position first. If you are on a supplement, price a new Medigap policy and ask about underwriting before you drop anything; if you are on Advantage, map out your return path before switching to Original Medicare.
- Confirm other coverage. If you have employer, union, VA, TRICARE, or Medicaid coverage, talk to that benefits administrator before changing Medicare coverage.
If you want to go deeper on evaluating candidates against your current plan, it helps to explore your Medicare plan switching options as a broader topic — this enrollment-period decision is one part of that larger comparison.
Key Takeaways
- Four main windows: Initial Enrollment, Open Enrollment (Oct 15–Dec 7), Advantage Open Enrollment (Jan 1–Mar 31), and event-based Special Enrollment Periods.
- Open Enrollment changes take effect January 1; SEP changes generally take effect the first of the following month.
- The annual Open Enrollment Period does not guarantee a right to buy or switch Medigap without underwriting — Medigap rights are separate and, in most states, narrow.
- A plan termination is not the same as a benefit change; it triggers its own replacement rights and deadlines.
- If a move, coverage loss, or plan exit happens to you, confirm your exact SEP window with 1-800-MEDICARE or your State Health Insurance Assistance Program (SHIP) before assuming you can or cannot change.
When a window opens for you, gather your current plan’s annual notice, your medication list, and your doctors’ names, then compare plans available in your ZIP code side by side — that comparison, done before the deadline, is what turns an enrollment period into a better-fitting plan.