Medicare Enrollment Periods: Key Dates and Details for 2026
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Last Updated July 25, 2026
Figuring out Medicare can feel overwhelming. The variety of enrollment periods and specific timelines only adds to the confusion. To help, we've detailed the key Medicare enrollment periods for 2026 below. Understanding these periods can help you get the coverage you need without unnecessary penalties or delays.
Medicare Enrollment Periods Chart
Here are the key Medicare dates at a glance. Bookmark this chart and refer back whenever you need a quick reminder of when you can enroll or make changes:
| Enrollment Period | Dates | Who It's For | What You Can Do |
|---|---|---|---|
| Initial Enrollment Period (IEP) | 7 months around your 65th birthday month | People aging into Medicare | Enroll in Parts A, B, C, and D |
| General Enrollment Period (GEP) | January 1 – March 31 | People who missed their IEP | Sign up for Part A and/or Part B |
| Annual Enrollment Period (AEP) | October 15 – December 7 | All Medicare beneficiaries | Switch or drop Advantage and Part D plans |
| Medicare Advantage OEP | January 1 – March 31 | People already on Medicare Advantage | One-time switch or return to Original Medicare |
| Special Enrollment Period (SEP) | Triggered by a qualifying life event | People with a qualifying event (move, loss of coverage, etc.) | Enroll or change coverage outside standard windows |
| Medigap Open Enrollment Period | 6 months from Part B start date at 65 | People new to Part B at 65 | Buy any Medigap policy with no underwriting |
Initial Enrollment Period (IEP)
What is it? The Initial Enrollment Period is your first opportunity to sign up for Medicare. This period is crucial because missing it can result in penalties and delayed coverage.
When is it? The IEP spans seven months:
- Three months before the month you turn 65
- The month you turn 65
- Three months after the month you turn 65
What can you do during the IEP?
- Enroll in Original Medicare (Parts A and B)
- Sign up for a Medicare Advantage plan (Part C)
- Enroll in a Medicare Part D prescription drug plan
Important Tip: If you’re already receiving Social Security benefits when you turn 65, you will be automatically enrolled in Original Medicare (Parts A and B). However, you still need to sign up for Part D if you need prescription drug coverage.
General Enrollment Period (GEP)
What is it? The General Enrollment Period is for those who missed their Initial Enrollment Period and do not qualify for a Special Enrollment Period.
When is it? January 1 to March 31 each year.
What can you do during the GEP?
- Sign up for Medicare Part A and/or Part B
Important Note: Coverage begins the first day of the month after you enroll (a change from the old July 1 rule, thanks to the Consolidated Appropriations Act of 2021). You may still owe late enrollment penalties for the months you went without Part B.
Annual Enrollment Period (AEP)
What is it? The Annual Enrollment Period is the main time each year when you can make changes to your Medicare coverage.
When is it? October 15 to December 7 each year.
What can you do during the AEP?
- Switch from Original Medicare to a Medicare Advantage plan or vice versa
- Change from one Medicare Advantage plan to another
- Join, drop, or change Medicare Part D prescription drug plans
Important Tip: Changes made during the AEP take effect on January 1 of the following year. If you realize you chose the wrong plan during AEP, don't panic—you still have options.
Do I need to do anything for Annual Enrollment Period (AEP)?
Yes. Always, Always Always, review your current plan info and compare it to the other plans that are available. Plans change every year and it is imperative that you review your plan so that you are not stuck on something that isn't good for you anymore.Medicare Advantage Open Enrollment Period (MA OEP)
What is it? This period allows those already enrolled in a Medicare Advantage plan to make a one-time change.
When is it? January 1 to March 31 each year.
What can you do during the MA OEP?
- Switch to another Medicare Advantage plan with or without prescription drug coverage
- Disenroll from your Medicare Advantage plan and return to Original Medicare
Important Note: If you switch to Original Medicare during this period, you can also join a Medicare Part D plan. If you missed AEP, the MA OEP may still give you options. For a complete guide to the process and potential pitfalls, see how switching from Medicare Advantage back to Original Medicare works.
Can I switch from a Medicare Advantage plan to a Supplemental/Medigap plan during the Annual Enrollment Period without answering health questions?
Generally you need to answer health questions when going from an MAPD pan to a Med Supp. If you do it within the first year you are in the MAPD plan you can usually make the switch on a guaranteed issue basis. You aren't restricted to the annual enrollment period. You can also do it during open enrollment (Jan 1-Mar 31). If you change to a Med Supp you will also need to add a drug plan (PDP) and any supplemental coverage you desire but the supplemental coverage can be added at any time if you qualify for it.Special Enrollment Period (SEP)
What is it? Special Enrollment Periods are triggered by certain life events that allow you to make changes to your Medicare plan outside the usual enrollment periods.
When is it? The timing and duration of a SEP depend on the qualifying event. Common events include:
- Moving out of your plan’s service area
- Losing your current health coverage
- Changes in your eligibility for Medicaid or Extra Help
- Changes in your plan’s contract with Medicare
What can you do during a SEP?
- Enroll in Medicare Part A and/or Part B
- Switch or change your Medicare Advantage or Part D plan
Important Note: The length of your SEP varies, typically lasting 2-3 months from the time of the qualifying event.
Medicare Supplement (Medigap) Open Enrollment Period
What is it? This is the best time to buy a Medicare Supplement (Medigap) policy, which can help cover additional costs not covered by Original Medicare.
When is it? The six-month period starts the first day of the month you turn 65 and have enrolled in Medicare Part B.
What can you do during this period?
- Purchase any Medicare Supplement policy available in your state without medical underwriting
Important Note: If you miss this period, you may not be able to buy a Medigap policy, or it could be more expensive due to medical underwriting.
Avoiding Penalties
According to Medicare.gov, missing certain enrollment periods can result in penalties:
- Part B Penalty: If you do not sign up for Part B when first eligible, you may have to pay a late enrollment penalty, which is a 10% increase in your Part B premium for each 12-month period you could have had Part B but didn’t.
- Part D Penalty: If you go without Part D or other creditable prescription drug coverage for more than 63 days after your IEP, you may pay a late enrollment penalty, which is calculated based on how long you went without coverage.
Frequently Asked Questions
What are the 3 main Medicare enrollment periods?
The three most common Medicare enrollment periods are the Initial Enrollment Period (IEP) when you first become eligible at 65, the Annual Enrollment Period (AEP) each fall from October 15 to December 7, and the General Enrollment Period (GEP) from January 1 to March 31 for people who missed their IEP. Most people will only ever use the IEP and the AEP.
Do I have to re-enroll in Medicare every year?
No. Once you're enrolled in Medicare, your coverage renews automatically each year. You only need to take action during AEP if you want to change your plan, switch between Original Medicare and Medicare Advantage, or update your Part D prescription drug coverage.
When is the deadline to sign up for Medicare Part B?
Your Part B deadline depends on your situation. If you're aging in, your IEP ends three months after the month you turn 65. If you delayed Part B because you had job-based coverage, you get an 8-month Special Enrollment Period after that coverage ends. Miss both, and you'll need to wait for the GEP (January 1 to March 31) and may owe a lifetime late enrollment penalty.
Key Takeaways
Understanding the various Medicare enrollment periods is crucial for getting the coverage you need without facing penalties or coverage gaps. Mark these important dates on your calendar:
- IEP: Three months before to three months after your 65th birthday month
- GEP: January 1 to March 31
- AEP: October 15 to December 7
- MA OEP: January 1 to March 31
- SEP: Varies based on life events
- Medigap OEP: Six months starting the first day of the month you turn 65 and are enrolled in Part B
By keeping these dates in mind and understanding what actions you can take during each period, you can make informed decisions about your Medicare coverage and avoid unnecessary penalties. If you’re already enrolled in Medicare Advantage, see what changes you can still make during OEP. For a practical guide, see what to review on your Medicare plan at the start of the year.
Additional Resources
For further information on each enrollment period and to explore your Medicare coverage options, visit the official Medicare website or consult with a licensed Medicare agent. You can also get free, unbiased Medicare counseling from your State Health Insurance Assistance Program (SHIP), or call 1-800-MEDICARE with questions about your rights. Timely enrollment and making the right coverage choices can significantly impact your healthcare costs and access to services.
This guide aims to provide you with clear, accurate information about Medicare enrollment periods. Ensure you review your specific situation and consult with Medicare experts to make the best decisions for your health coverage needs.