Medicare Guide

How to Change or Switch Medicare Plans

Most people can change Medicare coverage at least once a year, but which changes are allowed — and when — depends on the coverage you have now and the window you are in. This guide walks through the three main change windows, the Medigap rules that work differently, and the steps that keep a switch from creating a gap, a penalty, or a surprise about your doctors.

Reviewed by Jeremy Weiser, Licensed Insurance Agent since 2007 · Published May 15, 2026 · Last updated August 14, 2026

Quick answer

When you can switch depends on the window: AEP each fall for everyone, Medicare Advantage Open Enrollment each winter for MA members, and Special Enrollment Periods after certain life events.

The Annual Enrollment Period (October 15 to December 7) is the yearly chance for anyone to change Medicare Advantage or Part D coverage for the following year. People already in a Medicare Advantage plan get one more chance from January 1 to March 31. Outside those windows, changes generally require a qualifying life event. Medicare Supplement (Medigap) changes work differently: you can apply any time of year, but outside protected windows the insurer can usually ask health questions.

Key takeaways

The Annual Enrollment Period runs October 15 through December 7; changes take effect January 1, and if you make several changes, the last one submitted is the one that counts.
Medicare Advantage Open Enrollment runs January 1 through March 31: one switch to a different Medicare Advantage plan, or a return to Original Medicare with a Part D plan — but you cannot use it to move from Original Medicare into Medicare Advantage.
Outside those windows, changing Medicare Advantage or Part D coverage generally requires a Special Enrollment Period tied to a life event, like moving or losing other coverage.
Medigap is different: you can apply to switch supplements any time, but outside protected situations the new insurer can use medical underwriting — so never cancel an existing Medigap policy until the new one is approved and in force.
Before any switch, confirm your doctors are in the new plan's network and your prescriptions are on its drug list — premium alone is not enough reason to move.
Going 63 or more days in a row without creditable drug coverage can create a lifelong Part D late enrollment penalty, so line up replacement drug coverage before dropping any.

Change windows at a glance

Four ways coverage can change, each with its own rules

The right window depends on what you have today — Medicare Advantage, Original Medicare with a Part D plan, or Original Medicare with a Medigap supplement — and on what has changed in your life. Start by identifying your current coverage path, then match it to the window.

Annual Enrollment Period

Oct 15 - Dec 7Anyone with Medicare can change Medicare Advantage or Part D coverage; changes start January 1.

MA Open Enrollment

Jan 1 - Mar 31Medicare Advantage members only: one switch, effective the first of the month after the plan gets the request.

Special Enrollment Periods

Event-basedMoving, losing coverage, Medicaid or Extra Help changes, and other events each have their own window.

Medigap switches

Any time*Applications are accepted year-round, but outside protected windows the insurer can ask health questions.

Start with the coverage you have today

The rules for switching depend on your starting point. People in a Medicare Advantage plan have the most scheduled chances to change. People with Original Medicare plus a stand-alone Part D plan can change drug plans during the Annual Enrollment Period or with a Special Enrollment Period. People with a Medigap supplement follow insurance-company rules rather than Medicare enrollment windows for the supplement itself. Knowing which path you are on tells you which window applies.

The Annual Enrollment Period: everyone's yearly review

From October 15 through December 7, anyone with Medicare can join, drop, or switch a Medicare Advantage plan; move between Original Medicare and Medicare Advantage; or change stand-alone Part D drug plans. Changes made during this window take effect January 1. Plans change their premiums, networks, benefits, and drug lists every year, so even people who are happy with their coverage benefit from an annual review — the plan you have next year is not necessarily the plan you have today, even if you never touch it.

Medicare Advantage Open Enrollment: the winter second chance

From January 1 through March 31, people already enrolled in a Medicare Advantage plan get one switch: to a different Medicare Advantage plan, or back to Original Medicare with the option to join a stand-alone Part D plan. The change takes effect the first of the month after the plan receives the request. This window cannot be used to move from Original Medicare into Medicare Advantage, to switch from one stand-alone Part D plan to another, or to make a second change after the first one is processed.

Special Enrollment Periods: changes triggered by life events

Outside the scheduled windows, Medicare Advantage and Part D changes generally require a qualifying event. Moving out of a plan's service area, losing employer or union coverage, gaining or losing Medicaid or Extra Help, and certain plan or contract changes each open their own window with their own timing. If something significant has changed in your life or coverage, it is worth checking whether a Special Enrollment Period applies before waiting for fall — our Special Enrollment Periods guide covers the common triggers in detail.

Switching Medigap supplements works differently

Medigap plans are standardized, so the same plan letter has the same Medicare benefits from any insurer — which makes premium comparison meaningful. You can apply to switch Medigap policies at any time of year. The catch is underwriting: outside your one-time six-month Medigap Open Enrollment window and certain guaranteed-issue situations, the new insurer can usually review your health history and can decline the application or price it based on health. Some states add extra protections, such as birthday or anniversary rules. The safe sequence is always the same: apply, get approved, confirm the start date, and only then cancel the old policy.

Moving between Medicare Advantage and Original Medicare with a supplement

Leaving Medicare Advantage for Original Medicare is easy on the Medicare side, but qualifying for a Medigap supplement usually involves underwriting if you are outside a protected window. Federal trial rights protect two situations: people who joined a Medicare Advantage plan when they were first eligible at 65 and leave within the first 12 months, and people who dropped a Medigap policy to try Medicare Advantage for the first time and return within 12 months. Outside those situations, get the Medigap application approved before you give up the Advantage plan — this is the switch where professional guidance earns its keep.

How the mechanics work when you switch

When you join a new Medicare Advantage plan or a new stand-alone Part D plan, enrollment in the new plan automatically ends the old one of the same type — you do not need to cancel it yourself, and trying to cancel first can create a gap. Returning to Original Medicare from Medicare Advantage is done through the new enrollment, through the plan, or through 1-800-MEDICARE. Before submitting anything, confirm three things in the new plan: your doctors and hospitals are in network, your prescriptions are on the drug list at a pharmacy you use, and the total yearly cost — premium plus expected copays — actually beats what you have.

Go deeper

Related Medicare guides

Use this page as your Medicare starting point, then jump into the specific topic that matches your situation.

Common questions

Questions people usually ask next

These answers are a starting point. Medicare details can change based on timing, other coverage, and where you live.

Can I change my Medicare plan any time I want?

Generally no. Medicare Advantage and Part D changes happen during the Annual Enrollment Period (October 15 to December 7), the Medicare Advantage Open Enrollment Period (January 1 to March 31, for people already in Medicare Advantage), or a Special Enrollment Period tied to a qualifying event. Medigap applications can be submitted any time, but health underwriting may apply.

Do I need to cancel my old plan when I switch?

Usually not. Joining a new Medicare Advantage plan or a new Part D plan automatically ends the old plan of the same type. The exception is Medigap: cancelling a supplement is a separate step, and it should only happen after the replacement policy is approved and in force.

What happens if I miss the Annual Enrollment Period?

If you are in a Medicare Advantage plan, you get one more chance between January 1 and March 31. Otherwise, you generally need a qualifying event for a Special Enrollment Period — or you wait for the next Annual Enrollment Period in the fall.

Will switching plans affect which doctors I can see?

It can. Medicare Advantage networks differ plan to plan, so always confirm your doctors, specialists, and hospital before switching. Moving to Original Medicare generally means you can see any provider who accepts Medicare, but supplement underwriting and drug coverage need to be arranged.

Can switching create a late enrollment penalty?

It can if drug coverage lapses. Going 63 or more days in a row without Part D or other creditable drug coverage can create a lifelong Part D late enrollment penalty, so replacement drug coverage should always start when the old coverage ends.

Official references

Sources checked for this guide

These guides are written in plain English, but the 2026 cost figures and coverage rules should stay tied to official Medicare and CMS source material.

Medicare.gov: Open Enrollment Medicare.gov: Joining a health or drug plan Medicare.gov: Special Enrollment Periods

About the reviewer

Jeremy Weiser · Licensed Insurance Agent since 2007 · Nevada license #566932

Jeremy Weiser is the CEO and a principal of The Medicare Store and has been a licensed insurance agent since 2007 (Nevada license #566932). With nearly two decades in health and Medicare insurance, he leads the standards behind the guidance The Medicare Store gives every client.

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