Medicare open enrollment, officially the Annual Enrollment Period (AEP), runs October 15 through December 7, 2026 for 2027 coverage. During this window, people who are already on Medicare can switch plans, change their drug coverage, or move between Medicare Advantage and Original Medicare. It is not the window for signing up for Medicare the first time. That happens around your 65th birthday.
Any changes you make during AEP take effect January 1 of the following year. If you miss the December 7 deadline, your current plan renews automatically and you generally cannot make changes until the next AEP — a full year away.
What’s Different for 2027
Most of this year’s changes are in Part D, the drug coverage. Here are the federal limits Medicare set for 2027:
- Yearly drug cost limit: $2,400, up from $2,100 in 2026. Once your out-of-pocket spending on covered Part D drugs reaches it, you pay nothing more for covered drugs for the rest of the year.
- Highest allowed Part D deductible: $700, up from $615. Some plans charge less, and some charge none.
- Part D base premium: $41.33 a month, up from $38.99. That is a national benchmark, not your bill. Your plan’s premium can be higher or lower, and your Annual Notice of Change shows the real number.
- Negotiated prices on 15 more drugs, including Ozempic, Wegovy, Rybelsus, Xtandi and Otezla, starting January 1, 2027. What you pay at the counter still depends on your plan’s tier and copay.
Put together, the plan that was cheapest for you this year may not be the cheapest next year. For the full list, see the seven Medicare changes for 2027.
What You Can Change During AEP
During the Annual Enrollment Period, existing Medicare beneficiaries can make the following changes:
- Switch from one Medicare Advantage plan to another — If your current plan raised premiums, dropped a doctor from its network, or changed what drugs it covers, AEP is when you move to a different Advantage plan in your area. New coverage begins January 1.
- Switch from Medicare Advantage back to Original Medicare — If you want broader provider access, fewer network restrictions, or your health needs have changed, AEP is the window to return to Original Medicare. You can also add a standalone Part D drug plan at the same time. Important: returning to Original Medicare does not automatically give you a Medigap policy — see the “What You Cannot Change” section below for why this matters.
- Switch from Original Medicare to Medicare Advantage — If you are currently on Original Medicare and want to try a Medicare Advantage plan — for added benefits like dental, vision, or hearing coverage, or to cap your out-of-pocket costs — AEP is the enrollment window. Coverage begins January 1.
- Join, switch, or drop a Part D drug plan — If your prescriptions are no longer covered under your current plan’s formulary, your drug costs have increased, or a better plan is available in your area, AEP is when you make that change. See our Part D guide for how Part D works and how to compare plans.
- Drop a Part D plan — If you are gaining creditable drug coverage from another source, you can drop your standalone Part D plan during AEP without penalty.
What You Cannot Change During AEP
The Annual Enrollment Period covers plan switching — it does not open the door to everything. These changes are not possible during AEP:
- Switching Medigap (Medicare Supplement) policies — This is the most common and costly misconception about AEP. The Annual Enrollment Period does not give you the right to change Medigap plans. Medigap has its own open enrollment window — the six months immediately after your Part B begins — during which insurers cannot reject you or charge more based on your health. After that window, in most states, insurers can underwrite based on your health history. AEP does not change this. If you want to switch Medigap plans outside your original open enrollment window, get advice from a Medicare advisor before assuming you can. See our Medicare Advantage vs. Medigap guide for how the two tracks compare.
- Enrolling in Medicare for the first time — AEP is for existing beneficiaries switching plans. If you are enrolling in Medicare for the first time, your Initial Enrollment Period — the seven-month window around your 65th birthday — is the right time to act, not AEP.
- Getting changes effective before January 1 — All AEP changes take effect January 1 of the following year, without exception. If you need coverage to change sooner because of a qualifying life event, a Special Enrollment Period may apply instead.
Why You Should Review Your Plan Every Year
Medicare plans are not locked in permanently. Insurers are allowed to change premiums, deductibles, copays, provider networks, and drug formularies every year. A plan that fit your situation in January may look very different by the following October.
By September 30, your plan is required to send you an Annual Notice of Change (ANOC). This document shows exactly what is changing in your plan for the coming year. Read it as soon as it arrives. Any increase to your premium, change to your network, or drug that has moved to a higher cost tier is a signal to shop during AEP. Doing nothing means your current plan renews automatically — which may be fine, or may cost you significantly more next year.
The right plan for last year may cost you significantly more next year if you do not review during AEP.
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How to Compare Plans Before Making a Change
AEP is not the time to guess. Here is a straightforward approach to comparing options before the window closes:
- Read your Annual Notice of Change first. Identify exactly what is changing in your current plan — premiums, network, drug coverage — before you look at anything else.
- List your doctors, specialists, and prescriptions. These are your comparison criteria. A plan with a low premium that doesn’t cover your medications or include your primary doctor is not a savings — it’s a liability.
- Use medicare.gov/plan-compare. Enter your zip code and prescriptions to see Advantage and Part D plans available in your area. The tool estimates annual costs based on your specific drug list.
- Check total annual costs, not just monthly premiums. Add up premium + deductible + expected copays for a realistic cost comparison. A $0-premium plan can still cost more than a plan with a modest monthly cost if its copays are higher.
- Confirm provider network before switching to an Advantage plan. Call the plan directly or use their online directory to verify your doctors are in-network before you enroll.
For a deeper look at how Medicare Advantage and Original Medicare compare as coverage tracks, see our Medicare Advantage vs. Original Medicare guide.
Missed December 7? A Second Chance for Medicare Advantage Members
If you are in a Medicare Advantage plan on January 1, you get one more window: January 1 through March 31. You can make one change, either to a different Advantage plan or back to Original Medicare with a Part D drug plan. The new coverage starts the first of the next month.
This window does not help people on Original Medicare who want to join an Advantage plan. That move still has to happen in the fall.
Your 2027 Open Enrollment Checklist
Work through these before December 7, 2026:
- Read your Annual Notice of Change. Plans must send it by September 30. Circle any change to your premium, deductible, drug coverage, or doctor network. The Medicare Plan Checkup can read it with you and show each change in dollars.
- Write down every prescription with its dose, plus your doctors and your pharmacy. That list is what you are shopping against.
- Run your drug list through medicare.gov/plan-compare once the 2027 plans are posted in early October. Sort by estimated total yearly cost, not by premium.
- Check each drug’s tier and any prior authorization rule in the plans you are considering. A drug that moved up a tier can cost more over a year than the difference in premiums.
- Leaving Medicare Advantage for Original Medicare? Find out whether you can get a Medigap policy before you switch. In most states, insurers can turn you down or charge more once your first Medigap window has passed.
- Enroll by December 7 and keep the confirmation number. Don’t leave it to the last week, when phone lines and websites are busiest.
- In early January, check that your new card arrived and that your pharmacy has the new plan on file.
Missing the December 7 deadline means your current plan renews automatically and you cannot make changes until the next Annual Enrollment Period.
🆓 Don’t navigate enrollment alone — free help is available.
Our partner Chapter Medicare can help you confirm your enrollment window, avoid penalties, and choose the right plan before your deadline.
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Disclosure: We may receive a referral from Chapter if you choose to use their service. Chapter is a licensed health insurance agency and is not affiliated with or endorsed by Medicare or any government agency.
Related Medicare guides
Medicare Advantage vs. Original Medicare — How the two coverage tracks compare, and which may be right for your situation
Medicare Advantage vs. Medigap — What Medigap covers, how it differs from Advantage, and the Medigap enrollment window rules
Medicare Special Enrollment Periods — When you can make changes outside AEP, and how long each window lasts
Free Medicare Help from Chapter Medicare — What Chapter is, who they help, and what to expect before you call
Medicare Overview — How Medicare is structured, what each part covers, and how to navigate the system
