Medicare Fall Open Enrollment (AEP): Your Complete Guide

Updated June 4, 20269 min readReviewed against medicare.gov

Medicare's fall Open Enrollment Period — also called the Annual Election Period or Annual Enrollment Period (AEP) — runs from October 15 to December 7 every year. During this window you can join, drop, or switch a Medicare drug (Part D) plan, switch between Original Medicare and a Medicare Advantage plan, or move from one Medicare Advantage plan to another. Any change you make takes effect on January 1 of the following year, as long as the plan receives your request by December 7. You cannot sign up for Part A or Part B during this period — that uses a different enrollment window.

What is the fall Open Enrollment Period and when is it?

The Medicare fall Open Enrollment Period runs from October 15 to December 7 every year. You may see it called by several names — the Annual Election Period, the Annual Enrollment Period, or simply AEP — but they all refer to the same window with the same dates.

This is the main once-a-year chance for most people to review their coverage and switch plans. Any change you make takes effect on January 1 of the next year, provided the plan receives your enrollment request on or before December 7. If you make several changes, only your final choice before the deadline counts.

Window: October 15 – December 7 (same dates every year)
Changes take effect: January 1 of the following year
Deadline: the plan must receive your request by December 7

What changes can you make during fall Open Enrollment?

Fall Open Enrollment is flexible. You can make as many changes as you like during the window — there is no limit — and the last change you make before December 7 is the one that takes effect on January 1.

Important: this period does NOT cover signing up for Part A or Part B. Enrolling in Original Medicare itself is handled through your Initial Enrollment Period, the General Enrollment Period, or a Special Enrollment Period — not the fall Open Enrollment Period.

Join, drop, or switch a Medicare drug (Part D) plan
Switch from Original Medicare to a Medicare Advantage plan
Switch from a Medicare Advantage plan back to Original Medicare (and add a Part D plan)
Switch from one Medicare Advantage plan to another, with or without drug coverage
You can make unlimited changes — only your final choice before Dec 7 counts
You cannot use this period to sign up for Part A or Part B for the first time

What about Medigap (Medicare Supplement)?

Medigap (Medicare Supplement) policies are not part of the fall Open Enrollment Period. There is no annual federal window that guarantees the right to buy or change a Medigap policy.

Your strongest guaranteed right to buy any Medigap policy sold in your state — regardless of your health — is your one-time, six-month Medigap Open Enrollment Period, which starts the month you are both 65 or older and enrolled in Part B. Outside of that window (and a few limited guaranteed-issue situations), an insurer can review your health history and may charge more or deny coverage. State rules vary, so check the specifics where you live before assuming you can switch.

The Annual Notice of Change — and why to review even if you're happy

If you have a Medicare Advantage or Part D plan, your plan must mail you an Annual Notice of Change (ANOC) before fall Open Enrollment begins — generally by September 30. The ANOC explains how your plan's costs, coverage, drug list (formulary), and provider network will change for the coming year.

Even if you are happy with your plan and do nothing, your coverage usually renews automatically — but the plan's premiums, copays, covered drugs, or network can change for next year. Reading the ANOC takes a few minutes and is the best way to catch a change that affects you, such as a drug being dropped or a doctor leaving the network. If nothing important changed for you, you do not need to take any action; your current plan continues into the new year.

ANOC arrives by around September 30
It lists next-year changes to cost, coverage, drug list, and network
Doing nothing renews most plans automatically — but at next year's terms
Review the ANOC so an unwelcome change doesn't surprise you in January

2026 costs to weigh when comparing plans

When you compare drug plans and Medicare Advantage plans, look at the total picture — premiums, deductibles, copays, the drugs covered, and provider networks — not just the monthly premium. The figures below are set nationally for 2026 and provide useful reference points.

Higher-income enrollees may also owe an income-related monthly adjustment amount (IRMAA) on top of their plan premium. For 2026, IRMAA is based on your 2024 modified adjusted gross income (MAGI) and starts above $109,000 for a single filer or $218,000 for a married couple filing jointly.

Part B standard premium: $202.90/month; Part B deductible: $283/year; Part B coinsurance: 20%
Part A: premium-free with 40+ work-credit quarters ($311/month at 30–39 quarters; $565/month under 30); Part A deductible: $1,736 per benefit period
Part D out-of-pocket spending cap: $2,100/year (a key 2026 protection)
Part D national base beneficiary premium: $38.99/month (used to figure the late penalty)
Part D IRMAA surcharge for higher earners: $14.50 – $91.00/month on top of the plan premium

Late penalties and missing the December 7 deadline

Enrolling in a Part D plan during Open Enrollment can help you avoid the Part D late enrollment penalty, which applies if you go without creditable drug coverage for too long. The penalty is 1% of the national base beneficiary premium ($38.99 for 2026) multiplied by the number of full months you went without coverage, rounded to the nearest $0.10, and it is added to your premium for as long as you have Part D.

The separate Part B late enrollment penalty — 10% of the Part B premium for each full 12-month period you were eligible but not enrolled, added for life — is not affected by fall Open Enrollment, because you cannot sign up for Part B during this window.

If you miss the December 7 deadline, you generally must keep your current coverage for the year unless you qualify for a Special Enrollment Period. There are two other windows that can still help certain people: the Medicare Advantage Open Enrollment Period and the General Enrollment Period.

Medicare Advantage Open Enrollment Period (MA OEP): January 1 – March 31, for people already in a Medicare Advantage plan. You may make one change — switch to another MA plan or return to Original Medicare (and add a Part D plan). You cannot use it to join Medicare Advantage for the first time.
General Enrollment Period (GEP): January 1 – March 31, for people who missed signing up for Part A and/or Part B. Coverage begins the month after you enroll. This is for Original Medicare enrollment — not the same as the AEP.

How to compare plans and make your change

The most reliable way to compare your options is the official Plan Finder at Medicare.gov, where you can enter your prescriptions and pharmacies to see your estimated total yearly cost under each plan. You can enroll online there, call 1-800-MEDICARE (1-800-633-4227), or contact the plan directly.

Free, unbiased one-on-one help is available from your State Health Insurance Assistance Program (SHIP). Note: medicareloginguide.com is an independent resource and is not affiliated with or endorsed by Medicare or any government agency; always confirm details with Medicare.gov or your plan before acting.

Frequently asked questions

Can I sign up for Medicare Part A or Part B during fall Open Enrollment?

No. The fall Open Enrollment Period (Oct 15–Dec 7) is only for changing Part D drug plans and Medicare Advantage plans. Signing up for Part A or Part B uses a different window — your Initial Enrollment Period, the General Enrollment Period (Jan 1–Mar 31), or a Special Enrollment Period.

Do I have to do anything if I'm happy with my current plan?

Usually no — most Medicare Advantage and Part D plans renew automatically, so you can keep your coverage by doing nothing. But your plan's costs, drug list, and network can change for the new year. Read the Annual Notice of Change (sent by about September 30) so you aren't surprised by a change in January.

How many times can I change my plan during Open Enrollment?

There is no limit. You can switch as many times as you want between October 15 and December 7. Only your final choice received by December 7 takes effect, starting January 1.

What is the difference between the AEP and the Medicare Advantage Open Enrollment Period?

The fall AEP (Oct 15–Dec 7) is open to almost everyone with Medicare and allows many types of changes. The Medicare Advantage Open Enrollment Period (Jan 1–Mar 31) is only for people already enrolled in a Medicare Advantage plan, who may make just one change — switch MA plans or return to Original Medicare with a Part D plan. You cannot join Medicare Advantage for the first time during the MA OEP.

Can I buy or change a Medigap policy during fall Open Enrollment?

Fall Open Enrollment does not cover Medigap (Medicare Supplement) policies. Your guaranteed right to buy any Medigap policy is your one-time six-month Medigap Open Enrollment Period, which begins when you're 65 or older and enrolled in Part B. Outside that window, insurers may use your health history to set the price or deny coverage, and rules vary by state.

What happens if I miss the December 7 deadline?

You generally keep your current coverage for the next year unless you qualify for a Special Enrollment Period. People already in a Medicare Advantage plan get one more chance during the MA OEP (Jan 1–Mar 31), and those who missed Part A or Part B can use the General Enrollment Period (Jan 1–Mar 31).

Sources

Related guides

Costs & Premiums

Medicare Enrollment Periods: IEP, GEP, AEP, and SEPs

Medicare Login Guide is an independent resource and is not affiliated with or endorsed by Medicare, the Centers for Medicare & Medicaid Services, or any government agency. This article is for general information only — confirm current figures and your specific options at medicare.gov or by calling 1-800-MEDICARE.