Can I Change My Medicare Plan Later?
Key Points
- Annual Enrollment Period (Oct 15–Dec 7) is the main window to change Medicare coverage each year.
- Medicare Advantage enrollees have an additional Open Enrollment Period from Jan 1–Mar 31.
- Special Enrollment Periods allow changes outside the standard windows for qualifying life events.
Medicare is not a set-it-and-forget-it decision. There are defined windows each year when you can switch plans — and certain life events that open additional opportunities to make changes.
Annual Enrollment Period — October 15 to December 7
The Annual Enrollment Period (AEP) is the primary window each year when Medicare beneficiaries can make changes to their coverage. During this period, you can switch from Original Medicare to Medicare Advantage, switch from Medicare Advantage back to Original Medicare, change from one Medicare Advantage plan to another, join a Part D plan, switch Part D plans, or drop Part D coverage.
Changes made during AEP take effect on January 1 of the following year. This is the most important enrollment period for most beneficiaries, and it's worth reviewing your coverage every year — plan networks, formularies, and premiums change annually.
Medicare Advantage Open Enrollment — January 1 to March 31
If you are already enrolled in a Medicare Advantage plan, you have an additional window at the start of each year. Between January 1 and March 31, you can switch to a different Medicare Advantage plan or return to Original Medicare (and enroll in a stand-alone Part D plan). Changes during this period take effect the first day of the month after your plan receives your enrollment request.
This period does not apply to people on Original Medicare — it is specifically for those already in a Medicare Advantage plan who want to make a change.
Special Enrollment Periods
Life doesn't always follow a schedule, and Medicare accounts for that with Special Enrollment Periods (SEPs). Certain events can trigger a SEP that allows you to make coverage changes outside the standard enrollment windows. Common qualifying events include moving out of your plan's service area, losing other health coverage, your plan leaving the market, or qualifying for low-income assistance programs.
The duration and specifics of each SEP vary depending on the triggering event. Not all changes are available through every SEP — so it's important to understand which changes you're eligible to make and within what timeframe.
Medigap Enrollment Is Different
Switching Medigap plans is governed by different rules. The best time to enroll in a Medigap plan is during your Medigap Open Enrollment Period — the six months starting the month you're both 65 and enrolled in Part B. During this window, insurers cannot use medical underwriting to deny you coverage or charge you higher premiums based on health conditions.
Outside of this initial window, most states allow insurers to use medical underwriting — meaning your health history could result in a higher premium or even denial of coverage. This is why choosing your Medigap plan at the right time matters so much.
Still Have Questions?
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