What is the Medicare Advantage Open Enrollment Period (January 1 to March 31)?

Updated October 28, 2026 · General information, not professional advice

Short answerThe Medicare Advantage Open Enrollment Period runs January 1 to March 31 each year. If your parent is in a Medicare Advantage plan, they can make one change: switch to a different Medicare Advantage plan, or drop it and go back to Original Medicare, with the option to add a Part D drug plan. The change starts the first day of the month after the plan gets the request. It's separate from fall Open Enrollment, October 15 to December 7.

Two different open enrollment windows

Fall Open Enrollment, October 15 to December 7: anyone with Medicare can switch between Original Medicare and Medicare Advantage, change Medicare Advantage plans, or join, switch or drop a Part D drug plan. Changes start January 1.
Medicare Advantage Open Enrollment, January 1 to March 31: only for people already in a Medicare Advantage plan, and only one change.

The January window is a safety net: if your parent picked a plan in the fall and finds in January that a doctor isn't in network or a drug costs more than expected, there's still a way out.

What your parent can do from January 1 to March 31

Switch to a different Medicare Advantage plan, with or without drug coverage.
Drop Medicare Advantage and return to Original Medicare, and join a standalone Part D drug plan at the same time.

Only one change is allowed in the window. It takes effect the first day of the month after the plan receives the request, so a request made January 15 starts February 1.

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What it doesn't allow

People in Original Medicare can't use it to join a Medicare Advantage plan or to switch Part D plans.
It doesn't guarantee a Medigap policy. In most states, a Medigap insurer can use medical underwriting if your parent buys a policy outside their Medigap open enrollment or a guaranteed-issue situation. Check before leaving Medicare Advantage if you'd want Medigap.

People new to Medicare who join a Medicare Advantage plan when they first enroll get a similar three-month window that starts when their Part A and Part B coverage begins.

How to make the change

Compare plans on Medicare.gov's Plan Finder with your parent's drug list, doctors and pharmacies.
To switch Medicare Advantage plans, enroll in the new plan; the old one ends automatically.
To go back to Original Medicare, join a standalone Part D plan (which ends the Medicare Advantage plan) or call 1-800-MEDICARE.
Keep the confirmation and watch for new member cards.

Free, unbiased help is available from your State Health Insurance Assistance Program (SHIP). This guide is general information, not insurance advice.

Common questions

When is the Medicare Advantage Open Enrollment Period?

January 1 to March 31 every year.

How many changes can I make from January to March?

One. Your parent can switch Medicare Advantage plans or return to Original Medicare (and add a Part D plan) once in that window.

When does the change take effect?

The first day of the month after the plan gets the request.

Can someone with Original Medicare join Medicare Advantage in January?

Not through this window. They'd generally wait for fall Open Enrollment, October 15 to December 7, unless they qualify for a Special Enrollment Period.