Medicare AEP 2026: What You Can Change October 15 to December 7

What Is the Medicare Annual Enrollment Period (AEP)?

The Medicare Annual Enrollment Period, sometimes called the Fall Open Enrollment Period or Annual Election Period, is the yearly window when people with Medicare can change their Medicare Advantage (Part C) and Medicare prescription drug (Part D) coverage. For the 2026 cycle, AEP runs from October 15, 2026 through December 7, 2026, and any elections you submit will take effect on January 1, 2027.

This period is set nationally by the Centers for Medicare and Medicaid Services (CMS). No matter where you live, the dates are the same. If your plan receives your enrollment request by December 7, your new coverage starts on the first day of the following year.

Why AEP matters even if you like your current plan

Medicare Advantage and Part D plans change every year. Premiums rise or fall, drug formularies shift, provider networks add and drop hospitals, and copays for common services get restructured. Even if you're happy right now, the plan you have in December may look very different in January. Treating AEP as a mandatory annual check-up (not just a switching window) is the single best way to avoid surprise costs.

What You Can Change During AEP 2026

During the October 15 to December 7 window, Medicare beneficiaries have broad flexibility to reshape their coverage. Here's exactly what's on the table:

• Switch from Original Medicare to a Medicare Advantage plan (or vice versa)
• Change from one Medicare Advantage plan to another, with or without drug coverage
• Join a Medicare Part D prescription drug plan for the first time
• Switch from one Part D plan to another
• Drop your Part D coverage entirely (though this may trigger a late-enrollment penalty later)
• Add or drop drug coverage on a Medicare Advantage plan

What AEP does NOT cover: Medigap has its own rules

This is one of the biggest points of confusion. AEP is not an open enrollment window for Medicare Supplement (Medigap) insurance. Medigap has its own separate enrollment period. The federal Medigap Open Enrollment Period is a one-time, six-month window that begins the first month you are both 65 or older and enrolled in Medicare Part B. During that six-month window, insurance carriers cannot deny you coverage or charge you more because of pre-existing conditions.

Outside of that window (or a guaranteed-issue situation), most states allow insurers to use medical underwriting. That means you can technically apply for a Medigap policy during AEP, but the carrier can review your health history, charge higher rates, or decline coverage entirely.

The Annual Notice of Change (ANOC) Letter

Every September, Medicare Advantage and Part D plans are required to send members an Annual Notice of Change (ANOC). This document spells out exactly how your plan will change on January 1 of the following year. You should receive it by September 30, either by mail or by email, depending on your communication preference.

The ANOC is often bundled with the Evidence of Coverage (EOC), which contains the full plan document. The ANOC is the quick-reference summary you should read first.

What to check on your ANOC letter

Read your ANOC with a highlighter in hand. Compare this year's numbers to next year's, and flag anything that changes materially. Focus on these five categories:

Using Medicare.gov Plan Finder to Compare Options

The official Medicare.gov Plan Finder (also called Plan Compare) is the most reliable tool for comparing 2027 Medicare Advantage and Part D plans in your ZIP code. It pulls directly from CMS's official plan data, so premium, formulary, and star-rating information is accurate.

Step-by-step: how to use Plan Finder

1. Go to Medicare.gov/plan-compare or click "Find plans" on the Medicare.gov homepage
2. Enter your ZIP code and confirm you want to see 2027 plans
3. Choose your plan type: Medicare Advantage or Medicare drug plan (Part D)
4. Add your prescription drugs with exact names, dosages, and monthly quantities
5. Select your preferred pharmacies (and consider mail-order for savings)
6. Review the list of plans, sorted by total estimated yearly cost
7. Check up to three plans and click "Compare" for a side-by-side view
8. When ready, click "Enroll" next to your chosen plan

The key metric to focus on is total estimated yearly cost, not just monthly premium. A $0-premium plan can easily cost more than a $40/month plan if its formulary drops your medications or its copays are higher.

What to verify outside Plan Finder

Plan Finder is a great starting point, but confirm these details before enrolling:

• Call your doctors and hospitals directly to verify they'll be in-network for 2027
• Review the plan's Summary of Benefits and Evidence of Coverage
• Check for prior-authorization requirements or step-therapy rules on your key medications
• If you have retiree or employer coverage, talk with your benefits administrator first

Your AEP 2026 Checklist

Use this checklist to work through AEP systematically instead of scrambling in the final week of November.

• September: Read your Annual Notice of Change letter carefully
• Early October: Make a list of every current doctor, specialist, and hospital
• Early October: List every prescription with name, dosage, and frequency
• October 15: AEP opens. Log in to Medicare.gov Plan Finder
• Compare at least three plans by total estimated yearly cost
• Verify your doctors and preferred pharmacy are in-network for 2027
• Confirm every medication is on the plan's formulary
• Check the maximum out-of-pocket (MOOP) limit for Medicare Advantage plans
• Factor in travel plans, seasonal moves, and expected surgeries or care needs
• Consult a licensed independent Medicare broker if you have questions
• By December 7: Submit your enrollment. Save your confirmation number
• January 1, 2027: New coverage takes effect. Verify your ID card arrives

AEP vs. Medicare Advantage Open Enrollment Period (MA OEP)

AEP is not the only enrollment window for Medicare Advantage members. From January 1 through March 31 each year, there is a separate window called the Medicare Advantage Open Enrollment Period (MA OEP). Many people confuse these two, but the rules are very different.

During MA OEP, if you're already enrolled in a Medicare Advantage plan, you get one additional chance to switch to a different MA plan or drop back to Original Medicare (and add a stand-alone Part D plan if desired). What you cannot do during MA OEP: move from Original Medicare into a Medicare Advantage plan, or change your stand-alone Part D plan if you stayed on Original Medicare after AEP. In other words, MA OEP is a narrow safety net for Medicare Advantage members who made a choice during AEP that isn't working out.

Frequently Asked Questions

When does Medicare AEP end in 2026?

The Medicare Annual Enrollment Period ends on December 7, 2026. Your plan must receive your enrollment request by that date for coverage to begin January 1, 2027. If you miss the deadline, you generally have to wait until the next AEP unless you qualify for a Special Enrollment Period due to a life event such as moving or losing other coverage.

What is the difference between Medicare open enrollment and annual enrollment?

They are often used as the same term. "Medicare Open Enrollment" and "Medicare Annual Enrollment Period" both refer to the October 15 to December 7 window for changing Medicare Advantage and Part D coverage. However, the "Medigap Open Enrollment Period" is a completely different, one-time six-month window tied to when you first enroll in Part B at 65. Do not confuse them.

Can I enroll in a Medigap plan during AEP?

You can apply for a Medigap policy during AEP, but AEP does not give you any special guaranteed-issue rights for Medigap. Unless you are still within your six-month Medigap Open Enrollment Period or have a guaranteed-issue situation (like losing employer coverage), insurers in most states can use medical underwriting to deny you or charge higher premiums.

What happens if I do nothing during AEP?

If you take no action during AEP, your current Medicare Advantage or Part D plan will typically renew automatically for the next year, with the changes described in your Annual Notice of Change. This is fine if you've reviewed the ANOC and are comfortable with next year's premiums, formulary, and network. However, doing nothing without reading the ANOC is risky and can lead to unexpected costs on January 1.

How is AEP different from the Medicare Advantage Open Enrollment Period in January?

AEP (October 15 to December 7) is available to all Medicare beneficiaries and allows a broad set of changes, including switching between Original Medicare and Medicare Advantage. The MA OEP (January 1 to March 31) is only available to people already enrolled in a Medicare Advantage plan, and only lets them switch to a different MA plan or return to Original Medicare with a stand-alone Part D plan. You cannot use MA OEP to move from Original Medicare into Medicare Advantage.