What Are the 3 Enrollment Periods for Medicare?

Health Line

2 days ago

Medicare has an initial enrollment period around your birth month, open enrollment toward the end of the year, and special enrollment periods that vary depending on your circumstances.
Medicare enrollment periods happen at the same time each year and allow multiple opportunities to evaluate your healthcare coverage.
Depending on your circumstances, you may need to enroll during a specific enrollment period.
Medicare open enrollment period (OEP)
Medicare's open enrollment period (OEP) runs from October 15 to December 7 each year.
During open enrollment, you can change coverage within Medicare. For example, you can:
When do OEP changes take effect?
If you change your Medicare coverage during the annual open enrollment, your old coverage will end, and your new coverage will start on January 1 of the following year.
This means that if you made a change on November 3, 2025, it will take effect on January 1, 2026.
Medicare special enrollment period (SEP)
If you miss the 7-month window of your IEP, you may have an opportunity to sign up for Medicare during a special enrollment period (SEP). You may be eligible for a SEP in the following instances.
You have alternative insurance that will soon end
If you have group health insurance through an employer or union, COBRA, Medicaid, or other insurance that will soon end, this allows you to sign up anytime outside of your IEP. You can sign up for:
Original Medicare
Medicare Advantage
Part D prescription drug plans
You will have 2 to 3 months from the time your coverage ends to enroll in a new plan. But the exact timeframe will depend on your exact situation.
You change address
If you move state, move back to the United States after being abroad for a period of time, were incarcerated, or move out of a nursing home or rehabilitation facility, you may be able to:
enroll in Original Medicare
switch to a new Medicare Advantage plan that's available in your area
switch back to Original Medicare from Medicare Advantage
join a Part D prescription drug plan
You'll have around 2 months to enroll or make plan changes. But the exact time will depend on your individual circumstances.
Your plan's Medicare contract changes or ends
There are instances where your plan may become unavailable. This could be for various reasons, each with its own rules:
Medicare imposes a sanction on a plan: In this instance, you can switch plans from the time the sanction is imposed until it's removed.
The state takes over the plan for financial reasons: You can switch plans from when the state takes over until they hand it back to the company.
The plan's Medicare contract ends: Your opportunity to switch starts 2 months before the plan's Medicare contract ends, and ends 1 full month later.
The plan's contract is not renewed: In this instance, you can enroll in a new plan between December 8 and the last day of February.
Other circumstances may entitle you to a SEP, so it's important to contact Medicare or your plan provider if you have any enrollment questions.
Medicare general enrollment period (GEP)
This period runs from January 1 to March 31 each year.
Your coverage starts the month after you sign up. But if you're not eligible for a SEP, you might pay a monthly late enrollment penalty.
If you already have a Medicare Advantage plan, this period is also known as the Medicare Advantage open enrollment period. You can:
switch to another Medicare Advantage Plan
leave a Medicare Advantage Plan to return to Original Medicare (In this instance, you'll also be able to join a separate Medicare Part D prescription drug plan.)
Exceptions to initial enrollment periods
People with specific disabilities can enroll in Medicare, even if they're under age 65.
If you're eligible for Medicare because you have amyotrophic lateral sclerosis (ALS), you'll be automatically enrolled the first month you receive Social Security Disability Insurance (SSDI).
If you have end stage renal disease (ESRD), your Medicare coverage usually begins after 3 months of dialysis, though you may have to complete forms to enroll.
If you have another disability and receive SSDI, you'll be automatically enrolled after 24 months.
The bottom line
There are three main Medicare sign-up periods:
IEP: The IEP is a 7-month period beginning 3 months before your 65th birthday month and including your 65th birthday month through 3 months after your 65th birthday month.
OEP: This occurs from October 15 through December 7 each year for people needing to change coverage within Medicare.
GEP or Medicare Advantage open enrollment period: This runs from January 1 through March 31 every year for people who missed their IEP. Late enrollment penalties may apply if you don't qualify for a SEP. This period is also for those who want to switch or leave their Medicare Advantage plan.
A SEP is also available, but the timings of these will vary based on your circumstances, such as employer-based group health plans ending or returning to the U.S. from overseas.
You can apply for Medicare during one of these windows.