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.
Your enrollment window determines both the deadline and when new coverage can start. If you are also considering life insurance for your family or estate, guaranteed universal life rates are a separate budgeting question, unrelated to Medicare enrollment.
Initial Enrollment Period: Your First Chance to Choose
Your Initial Enrollment Period generally lasts seven months: the three months before you turn 65, your birthday month and the following three months. Eligibility through disability has its own timing. You need both Part A and Part B to join Medicare Advantage, or either part to join a standalone Part D plan. The plan must serve your area.
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 you already have Part A and are adding Part B for the first time, you can join Medicare Advantage during a window beginning three months before you first have both parts and ending two months afterward. Coverage generally starts the month after the plan receives your request, once both parts are effective.
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)
During October 15 through December 7, you can make the following changes, subject to plan eligibility:
- 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.
Check Medigap eligibility separately. Returning from Advantage to Original Medicare during fall enrollment does not generally create a right to buy Medigap without underwriting. Your federal six-month Medigap Open Enrollment Period starts the first month you are both 65 or older and enrolled in Part B. Outside it, underwriting may apply unless you have a guaranteed-issue right or additional state enrollment protections. Before canceling an existing policy, review what happens to Medigap when you choose Advantage and confirm any trial right or other opportunity to return.
Medicare Advantage Open Enrollment (January 1 – March 31)
Only people already in Medicare Advantage can use this window. From January 1 through March 31, you can make one change:
- 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
Qualifying life events can create Special Enrollment Periods. The event determines both the allowed changes and the deadline:
| 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 | Once monthly, join or switch standalone Part D, or leave Advantage with drug coverage for Original Medicare by joining standalone Part D; a Part D drug-management at-risk designation can restrict this right |
| Move back to the U.S. from abroad | 2 full months after the month you return |
| Plan contract with Medicare ends (plan termination) | If Medicare terminates the contract: 1 month before through 2 full months after. If the plan ends it or both agree: 2 months before through 1 full month after. Confirm the notice’s dates. |
| 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
You can switch standalone Part D during fall Open Enrollment for January 1 coverage, or through an applicable Special Enrollment Period. Advantage Open Enrollment lets current Advantage members change Advantage plans or return to Original Medicare and join standalone Part D; it does not let someone already in Original Medicare simply switch drug plans. When you switch directly between drug plans, old coverage ends when new coverage begins, so do not separately cancel it. Going 63 or more consecutive days without Part D or other creditable drug coverage after your initial enrollment opportunity may trigger a late penalty when you enroll.
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.