Research note · Calendars
Open enrollment & Medicare AEP calendar 2026 to 2027 (plain English)
Medicare's Annual Enrollment Period (AEP) runs October 15 to December 7 every year, so the 2026 AEP opens October 15, 2026, closes December 7, 2026, and the changes you make take effect January 1, 2027 (Medicare.gov, Medicare Open Enrollment). ACA Marketplace Open Enrollment for 2027 coverage runs November 1, 2026 to January 15, 2027 on HealthCare.gov. Enroll by December 15, 2026 for coverage that starts January 1, 2027 (HealthCare.gov, dates and deadlines). States that run their own Marketplace can set different deadlines (CMS); find yours at HealthCare.gov/marketplace-in-your-state.
America First Healthcare is a licensed independent insurance agency. We are not Medicare, and we are not a government agency. Enrollment happens on Medicare.gov, by calling 1-800-MEDICARE (1-800-633-4227, TTY 1-877-486-2048), on HealthCare.gov or your state Marketplace, or with a licensed agent. This page is educational. Verify every date on the official site before you act.
Every enrollment window at a glance (2026 to 2027)
| Window | Who it is for | Dates | What it lets you do | Official source |
|---|---|---|---|---|
| Compare 2027 Medicare plans | People with Medicare | From October 1, 2026 | Compare your current Medicare health or drug coverage with 2027 options before AEP opens | Medicare & You 2027 |
| Medicare Annual Enrollment Period (AEP) | People with Medicare | October 15 to December 7, 2026; coverage starts January 1, 2027 | Join, switch, or drop a Medicare Advantage Plan or a Medicare drug plan; switch between Original Medicare and Medicare Advantage | Medicare.gov |
| Medicare Advantage Open Enrollment Period (MA OEP) | People already in a Medicare Advantage Plan | January 1 to March 31, 2027 | Switch to another Medicare Advantage Plan, or return to Original Medicare and join a separate drug plan. One change only. | Medicare.gov |
| Medicare Initial Enrollment Period (IEP) | People turning 65 | 7 months: starts 3 months before the month you turn 65, ends 3 months after it | Sign up for Part A and Part B, and join a Medicare Advantage or drug plan | Medicare.gov |
| Medicare General Enrollment Period (GEP) | People who missed their IEP and have no Special Enrollment Period | January 1 to March 31, 2027; coverage starts the month after you sign up | Sign up for Part B (and Part A if you have to pay for it). A late enrollment penalty may apply. | Medicare.gov |
| Medigap Open Enrollment Period | People 65 or older who just got Part B | 6 months, starting the first day of the month you are 65 or older and enrolled in Part B | Buy any Medigap policy sold in your state, regardless of health | Medicare.gov |
| Medicare Special Enrollment Periods (SEPs) | People with a qualifying event | Varies by event; many last 2 full months after the event | Join, switch, or drop Medicare Advantage or drug coverage after a listed event | Medicare.gov |
| Marketplace Open Enrollment (HealthCare.gov) | People shopping for 2027 ACA Marketplace coverage | November 1, 2026 to January 15, 2027 | Enroll in, renew, or change a Marketplace plan for 2027 | HealthCare.gov |
| Marketplace January 1 deadline | Marketplace shoppers who want coverage on January 1 | Enroll by December 15, 2026 | Coverage starts January 1, 2027. Enroll December 16 to January 15 and coverage starts February 1, 2027. | HealthCare.gov |
| State-based Marketplace Open Enrollment | People in a state that runs its own Marketplace | Starts November 1; end dates are set by the state | Same as above, on your state's site | CMS, find your state |
| Marketplace Special Enrollment Period | People with a qualifying life event | Usually 60 days before or after the event | Enroll in or change a Marketplace plan outside Open Enrollment | HealthCare.gov |
| Medicaid and CHIP | People who qualify by income | Any time of year | Apply for free or low-cost coverage | HealthCare.gov |
Job-based plans run their own open enrollment on their own dates. Check with your employer.
When is Medicare AEP in 2026?
Medicare AEP is October 15 to December 7, 2026, and the dates are the same every year. Medicare.gov calls it "Medicare Open Enrollment." Plans and agents call it the Annual Enrollment Period, or AEP. Same window.
Your plan must receive your enrollment request by December 7, 2026. Coverage under the new plan starts January 1, 2027 (Medicare.gov).
You do not have to wait for October 15 to start looking. The Medicare & You 2027 handbook lists October 1, 2026 as the day to start comparing your current coverage with 2027 options at Medicare.gov/plan-compare (Medicare & You 2027). Your plan also sends an Evidence of Coverage notice by October 15 that explains what it covers and what you pay next year.
What can you change during AEP?
During October 15 to December 7 you can (Medicare.gov):
- Join, drop, or switch to another Medicare Advantage Plan, with or without drug coverage, or add or drop drug coverage.
- Join, drop, or switch to another Medicare drug plan (Part D) if you are in Original Medicare.
- Switch from Original Medicare to a Medicare Advantage Plan, or from a Medicare Advantage Plan back to Original Medicare.
AEP does not change your Part A or Part B enrollment. Signing up for Part A and Part B happens in your Initial Enrollment Period, the General Enrollment Period, or a Special Enrollment Period, described below.
AEP also does not create a guaranteed right to buy a Medigap (Medicare Supplement) policy. Medigap has its own window, described below.
What is the difference between AEP and the Medicare Advantage Open Enrollment Period?
People confuse the two because both are called "open enrollment." They differ in who can use them, what they allow, and when.
| Annual Enrollment Period (AEP) | Medicare Advantage Open Enrollment Period (MA OEP) | |
|---|---|---|
| Dates | October 15 to December 7 | January 1 to March 31 |
| Who can use it | Anyone with Medicare | Only people already in a Medicare Advantage Plan |
| Can you move from Original Medicare into Medicare Advantage? | Yes | No |
| Can you switch Medicare Advantage plans? | Yes | Yes, once |
| Can you return to Original Medicare? | Yes | Yes, and join a separate drug plan |
| Can you switch drug plans alone while staying in Original Medicare? | Yes | No |
| Coverage starts | January 1 | First of the month after the plan gets your request |
Sources: Medicare.gov, joining a plan and Medicare & You 2027.
AEP is the wide door. MA OEP is a narrow second chance for people already in a Medicare Advantage Plan. People new to Medicare who join a Medicare Advantage Plan also get a version of MA OEP during their first 3 months with both Part A and Part B (Medicare.gov).
When is ACA Marketplace Open Enrollment for 2027?
On HealthCare.gov, Open Enrollment for 2027 coverage runs November 1, 2026 to January 15, 2027 (HealthCare.gov, dates and deadlines):
- November 1, 2026: first day to enroll in, renew, or change a 2027 Marketplace plan.
- December 15, 2026: last day to enroll or change plans for coverage that starts January 1, 2027.
- December 16, 2026 to January 15, 2027: enroll in this stretch and coverage starts February 1, 2027.
- January 15, 2027: last day to enroll in or change a Marketplace plan for 2027 without a Special Enrollment Period.
If your state runs its own Marketplace, the start date is November 1 but the end date is set by the state, and CMS directs consumers to their state Marketplace for state-specific deadlines (CMS, Marketplace Open Enrollment fact sheet). Find your state's site at HealthCare.gov/marketplace-in-your-state.
What changed for 2027, including the higher out-of-pocket limit, is in when is Open Enrollment for 2027.
Other Medicare windows: Initial, General, and Medigap
Initial Enrollment Period (IEP). Your first chance to sign up for Part A and Part B lasts 7 months: 3 months before the month you turn 65 through 3 months after it. Sign up before your birthday month and coverage starts the month you turn 65. Sign up during or after it and coverage starts the next month (Medicare.gov, when coverage starts).
General Enrollment Period (GEP). If you missed your IEP and do not qualify for a Special Enrollment Period, you can sign up for Part B (and buy Part A if you do not get it premium-free) from January 1 to March 31 each year. Coverage starts the month after you sign up, and a late enrollment penalty may apply (Medicare.gov).
Special Enrollment Period for job-based coverage. If you delayed Part B because you or your spouse were still working and had group health coverage, you have 8 months to sign up after the group coverage or the employment ends, whichever happens first. COBRA does not count as group health plan coverage for this rule (Medicare.gov).
Medigap Open Enrollment Period. Your Medigap window is the 6-month period that starts the first day of the month you are 65 or older and enrolled in Part B. During it you have the right to buy any Medigap policy sold in your state. Outside it, there is no federal guarantee an insurer will sell you a policy, and it may cost more because of health problems. Some states add protections, so check your state insurance department (Medicare.gov, when to buy Medigap). For Medigap and other Medicare product basics, see Medicare.
Special Enrollment Periods (overview)
SEPs exist for certain life events. The rules differ for Medicare and the Marketplace.
Medicare Advantage and Part D SEPs. Medicare.gov lists the events and how long each window lasts (Medicare.gov, Special Enrollment Periods). Examples:
- You move out of your plan's service area: 2 full months after you move.
- You lose Medicaid eligibility: 3 full months from the date you lose eligibility or are notified.
- A 5-star plan is available in your area: one switch between December 8 and November 30 of the following year.
Marketplace SEPs. You usually have 60 days before or 60 days after a qualifying event, such as losing other coverage, moving, getting married, having a baby, or adopting a child (HealthCare.gov glossary). Medicaid and CHIP accept applications any time of year (HealthCare.gov).
This is not an exhaustive legal list. If you think you qualify, confirm on the .gov site that applies to you.
How to use this calendar in a Free Healthcare Review
Bring this page and your current cards or EOBs to a free healthcare review. Useful prep:
- Circle the next window that applies to you: Medicare AEP, Marketplace OE, MA OEP, or a possible SEP.
- Write one sentence: what you want to change, or keep, before that deadline.
- Walk the healthcare review checklist so documents and questions are ready.
AFHC can help you organize a household plan conversation. Official enrollment still happens on Medicare.gov, 1-800-MEDICARE, HealthCare.gov, your state Marketplace, or your plan. We do not invent dates, and we do not promise outcomes.
AEP and Open Enrollment season raise ad noise. Read medical insurance scams before you pay a cold-call pitch.
Related research
- Browse the research library.
- Prep documents with the healthcare review checklist.
- Read what underinsured means if you already have a card.
- Review Medicare basics on Medicare.
- Watch for OE-season pitches on medical insurance scams.
- Choosing between Medicare Advantage and a Supplement? Read the 2026 Medicare legislative shift.
- See why prescriptions cost so much in America's prescription drug price gap.
FAQ
When is AEP for Medicare?
Medicare AEP runs October 15 to December 7 every year. For 2026 that is October 15 to December 7, 2026, with changes effective January 1, 2027 as long as the plan receives your request by December 7. Confirm on Medicare.gov.
What does AEP stand for?
AEP stands for Annual Enrollment Period. Medicare.gov calls the same window Medicare Open Enrollment. It is the yearly period when people with Medicare can change Medicare Advantage and Part D drug coverage.
When is Marketplace Open Enrollment for 2027 coverage?
HealthCare.gov Open Enrollment for 2027 coverage runs November 1, 2026 to January 15, 2027. Enroll by December 15, 2026 for a January 1 start; enroll December 16 to January 15 for a February 1 start. State-based Marketplaces may set different end dates.
What is the Medicare Advantage Open Enrollment Period (MA OEP)?
If you are already in a Medicare Advantage Plan, MA OEP (January 1 to March 31) lets you make one switch to another Medicare Advantage Plan or return to Original Medicare and join a separate drug plan. You cannot use it to move from Original Medicare into Medicare Advantage, and you cannot use it to switch drug plans alone.
Can I enroll outside these windows?
Sometimes, through a Special Enrollment Period if you qualify. Marketplace and Medicare SEP rules differ. Start with HealthCare.gov or Medicare.gov. Do not rely on an unofficial date list.
Does AFHC enroll me on HealthCare.gov or Medicare.gov for me?
Official enrollment happens through Medicare.gov, 1-800-MEDICARE, HealthCare.gov, your plan, or a licensed agent. America First Healthcare is not Medicare and not a government agency. A free healthcare review helps you prepare documents, questions, and timing. It is educational help, not a guarantee you will beat a deadline or lower a premium.
Key takeaways
- Medicare AEP is October 15 to December 7, 2026. Changes take effect January 1, 2027.
- AEP changes Medicare Advantage and Part D coverage. It does not change Part A or Part B enrollment or create a Medigap guarantee.
- MA OEP (January 1 to March 31) is only for people already in a Medicare Advantage Plan, and it allows one change.
- HealthCare.gov Open Enrollment for 2027 coverage is November 1, 2026 to January 15, 2027. Enroll by December 15 for a January 1 start. State-based Marketplaces set their own end dates.
- IEP lasts 7 months around your 65th birthday. GEP is January 1 to March 31. Medigap Open Enrollment is 6 months from the first month you are 65 or older with Part B.
- Enroll on Medicare.gov, 1-800-MEDICARE, HealthCare.gov, your state Marketplace, or with a licensed agent. Verify every date on the official site.
Method / disclaimer
Dates above were verified on Medicare.gov, the Medicare & You 2027 handbook, HealthCare.gov, and CMS.gov on 2026-10-06. Government sites update. Verify before you act. America First Healthcare is a licensed independent insurance agency, not Medicare and not a government agency. This page is educational only, not medical, legal, or personalized insurance advice.
Next step
If you want help walking your calendar and paperwork in plain English before October 15, start a free healthcare review.
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Medicare timing and product basics: Medicare.