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The Medicare Annual Enrollment Period (AEP) runs October 15 through December 7, 2026. Any changes you make during this window take effect January 1, 2027. This is your one guaranteed opportunity each year to switch between Original Medicare and Medicare Advantage, change your Medicare Advantage plan, or add, switch, or drop a Part D prescription drug plan. If you are happy with your current coverage and nothing significant changed in your health or your plan’s benefits, you do not need to do anything.
Key Takeaways
- Medicare AEP: October 15 – December 7, 2026. Changes take effect January 1, 2027.
- You can switch between Original Medicare and Medicare Advantage, change MA plans, or add, switch, or drop Part D coverage.
- Medicare Advantage Open Enrollment Period (MA OEP): January 1 – March 31, 2027 — a separate, more limited window for MA enrollees only.
- Medicare Part B premium for 2026 is $202.90/month; the annual deductible is $283 (CMS).
- Review your Annual Notice of Change (ANOC) each fall — it tells you what changed in your plan’s premiums, benefits, and formulary for the coming year.
What Is the Medicare Annual Enrollment Period?
The Annual Enrollment Period is Medicare’s primary open enrollment window. It runs the same dates every year: October 15 through December 7. It applies to people who are already enrolled in Medicare (Parts A and B), not to people just becoming eligible for Medicare for the first time (who have their own Initial Enrollment Period).
During AEP, Medicare beneficiaries can make the following changes, all effective January 1 of the following year:
- Switch from Original Medicare (Parts A and B) to a Medicare Advantage plan (Part C)
- Switch from a Medicare Advantage plan back to Original Medicare
- Switch from one Medicare Advantage plan to a different Medicare Advantage plan
- Enroll in a standalone Part D prescription drug plan (if currently on Original Medicare with no drug coverage)
- Switch from one Part D plan to a different Part D plan
- Drop Part D coverage entirely (not recommended unless you have creditable drug coverage elsewhere)
If you do nothing during AEP, you stay in your current plan. Your plan may change its premiums, copays, or formulary for the new year — which is exactly why reviewing your Annual Notice of Change every fall matters.
Who Should Actively Review Their Coverage This AEP?
Not everyone needs to make a change, but these situations are strong signals to take a closer look:
- Your plan sent you an Annual Notice of Change (ANOC) showing premium increases, benefit reductions, or formulary changes that affect your prescriptions.
- Your health needs changed and your current plan no longer fits. For example, you started a new specialty prescription that is not covered on your current Part D formulary, or you need a specialist who is no longer in your MA network.
- You moved. Medicare Advantage plans are regional. If you moved, your plan may no longer cover your area, or better options may now be available.
- Your income changed and you want to check whether you qualify for the Low Income Subsidy (Extra Help) for Part D, which can significantly reduce prescription costs.
- You are dissatisfied with your current plan’s network, costs, or customer service and want to compare alternatives.
What Can You NOT Change During AEP?
AEP does not cover everything. You cannot use AEP to:
- Enroll in Medicare for the first time (use your Initial Enrollment Period or a Special Enrollment Period)
- Add or change a Medicare Supplement (Medigap) policy in most states without medical underwriting
- Enroll in Medicaid or Extra Help / Low Income Subsidy (these have year-round enrollment)
AEP vs. Medicare Advantage Open Enrollment Period: What Is the Difference?
The MA OEP is a second, more limited window for people who are already in a Medicare Advantage plan and want to make one change. It is not a full open enrollment — you cannot use the MA OEP to move from Original Medicare into an MA plan. That can only happen during AEP or your Initial Enrollment Period.
How Do You Make Changes During AEP?
You have three ways to enroll or switch plans:
1. Online. Go to Medicare.gov and use the Plan Finder tool to compare available plans in your area, filter by your prescriptions and preferred doctors, and enroll directly. This is the fastest method if you are comfortable using the site.
2. By phone. Call 1-800-MEDICARE (1-800-633-4227), available 24 hours a day, 7 days a week. TTY users can call 1-877-486-2048.
3. Through a licensed Medicare insurance broker or SHIP counselor. State Health Insurance Assistance Programs (SHIPs) offer free, unbiased counseling from trained volunteers. A SHIP counselor can help you compare plans without any sales pressure. Find your local SHIP at shiphelp.org.
What to Review Before AEP Closes
Do not rely on memory or last year’s plan details. Each fall your plan sends an Annual Notice of Change (ANOC) listing exactly what will be different in the new plan year. Before December 7, check:
- Premium. Did your Part B premium, MA plan premium, or Part D premium change? For 2026, Medicare Part B is $202.90/month with a $283 annual deductible (CMS). See the Medicare Part B 2026 guide for full coverage details.
- Drug formulary. Are your current prescriptions still covered at the same tier? A drug moving from Tier 2 to Tier 3 on your formulary can add hundreds of dollars in annual cost.
- Network. Are your doctors and preferred hospital still in the plan’s network?
- Extra benefits. Did your MA plan add or remove dental, vision, or hearing coverage?
- Star rating. Medicare rates plans on a 1-to-5 star scale. A plan that dropped stars may be worth shopping.
For a full breakdown of how Medicare Advantage compares to Original Medicare and how to decide between them, see the Medicare Advantage vs Original Medicare guide.
Frequently Asked Questions
When is Medicare open enrollment 2026?
The Medicare Annual Enrollment Period runs October 15 through December 7, 2026. Changes you make during this window take effect January 1, 2027.
Can I switch from Medicare Advantage to Original Medicare during AEP?
Yes. AEP lets you switch in either direction: from Original Medicare to Medicare Advantage, from Medicare Advantage back to Original Medicare, or from one MA plan to another.
What is the Medicare Advantage Open Enrollment Period?
The MA OEP runs January 1 through March 31 each year. It is only for people already enrolled in a Medicare Advantage plan. You can switch to a different MA plan or return to Original Medicare (and add a Part D plan). You cannot use the MA OEP to move from Original Medicare into an MA plan.
Do I have to do anything during AEP if I am happy with my plan?
No. If you are satisfied with your current coverage and nothing changed significantly in your plan’s benefits, premiums, or your health needs, you can do nothing and remain in your current plan for 2027. But do read your ANOC to confirm nothing material changed.
Where can I get free help comparing Medicare plans?
Your State Health Insurance Assistance Program (SHIP) provides free, unbiased plan comparison help from trained counselors. Find your local program at shiphelp.org. You can also compare plans at Medicare.gov using the Plan Finder tool.
Bottom line: Medicare AEP runs October 15 through December 7, 2026. Read your Annual Notice of Change, check whether your prescriptions are still on formulary, and confirm your doctors are still in-network. If something changed or you want to compare alternatives, use Medicare.gov or your local SHIP counselor before the December 7 deadline. See the Open Enrollment 2026 Complete Guide for the full enrollment picture across ACA and Medicare.
This article is for educational and informational purposes only and does not constitute insurance or financial advice. Medicare plan availability, premiums, and benefits vary by location and change annually. Verify current information at Medicare.gov or by calling 1-800-MEDICARE (1-800-633-4227). Free unbiased counseling is available through your State Health Insurance Assistance Program (SHIP) at shiphelp.org.
