The Medicare Annual Enrollment Period runs from October 15 through December 7 each year. During this window you can switch Medicare plans, add or drop prescription drug coverage, or move between Original Medicare and Medicare Advantage. Whatever you choose takes effect January 1 of the following year, so it’s the main yearly chance to adjust your coverage to how your health and finances have changed.1Medicare. Open Enrollment
What You Can Change Between October 15 and December 7
Your options depend on the coverage you have right now.
If you’re in Original Medicare (Parts A and B), you can switch to a Medicare Advantage Plan or join a standalone Part D prescription drug plan. If you’re already in a Medicare Advantage Plan, you can move to a different Medicare Advantage Plan, drop your plan and return to Original Medicare, or add or remove drug coverage. If you have a standalone Part D plan, you can switch to a different one or drop Part D altogether.1Medicare. Open Enrollment
One thing the AEP does not do: it isn’t your first-time sign-up window for Medicare itself. That’s the Initial Enrollment Period around your 65th birthday, or a Special Enrollment Period tied to losing employer coverage. The AEP is for people already on Medicare who want to change how their coverage is put together.
What to Do Before December 7
If you already have a Medicare Advantage or Part D plan, the plan is required to send you an Annual Notice of Change (ANOC) each September.2Medicare. Plan Annual Notice of Change (ANOC) It spells out every change coming for the new year: premiums, copays, provider network, and the drug formulary. Read it. A plan that fit you this year can quietly turn expensive or inconvenient next year.
Your plan also provides an Evidence of Coverage (EOC) document with the full detail on what’s covered, what you’ll pay, and what rules apply.3Medicare. Evidence of Coverage (EOC) The most practical way to decide whether to stay put is to hold the EOC against how you actually used your coverage this past year. Three questions do most of the work:
- Are your doctors still in-network for next year?
- Are your prescriptions still on the formulary, and at what tier?
- Once you add up premiums, copays, and expected out-of-pocket costs, is the total going up?
Drug coverage deserves its own look. The Inflation Reduction Act capped annual out-of-pocket spending on Part D drugs at $2,000 starting in 2025, and the cap adjusts to $2,100 for 2026.4Centers for Medicare & Medicaid Services. Final CY 2026 Part D Redesign Program Instructions If you take expensive medications, that cap can change which Part D plan actually saves you the most. Run the numbers in Medicare’s plan comparison tool before the window closes.
How to Actually Make the Change
You have three ways to enroll in or switch a plan. Use the online comparison tool at Medicare.gov/plan-compare to see costs, coverage, and star ratings side by side. Call 1-800-MEDICARE (1-800-633-4227) and have a representative walk you through your options. Or contact the plan you want to join directly, online or by phone.5Medicare. Joining a Plan
Have your Medicare number (from your red, white, and blue card) and your current plan details in front of you before you start. The plan must receive your enrollment request by December 7 for changes to take effect January 1.1Medicare. Open Enrollment
If you want unbiased help from someone who isn’t selling anything, contact your state’s State Health Insurance Assistance Program (SHIP). SHIP counselors are trained volunteers who can explain your options, compare plans with you, and even help with billing problems. You can find your local SHIP office through Medicare.gov or by calling 1-800-MEDICARE.
If You Change Your Mind in January
The AEP isn’t your only shot. The Medicare Advantage Open Enrollment Period runs January 1 through March 31 and gives people already in a Medicare Advantage Plan a chance to course-correct. During this window you can switch to a different Medicare Advantage Plan, or drop Medicare Advantage and return to Original Medicare with a standalone Part D plan. You get one plan change, and coverage begins the first of the month after the plan receives your request.6Medicare. Joining a Plan – Section: When to Join a Medicare Health or Drug Plan
Two limits are worth noting. This window is only for people already in a Medicare Advantage Plan on January 1; you cannot use it to join Medicare Advantage for the first time. And if you’re happy with Original Medicare, this window doesn’t do anything for you.
Thinking About Leaving Medicare Advantage? Read This First
If you’re considering dropping Medicare Advantage during the AEP and returning to Original Medicare, look at Medigap before you file the paperwork. Medigap policies cover costs Original Medicare leaves you with, such as copays and deductibles. (The 2026 Part B annual deductible is $283.7Medicare. 2026 Medicare Costs) Medigap enrollment rules are separate from the AEP, and missing them is costly.
Your Medigap Open Enrollment Period is a one-time, six-month window that starts the first day of the month you’re both 65 or older and enrolled in Part B.8Medicare. When Can I Buy a Medigap Policy During those six months, insurance companies must sell you any Medigap policy they offer at the standard rate, regardless of your health. Once that window closes, insurers can use medical underwriting: they can charge more based on pre-existing conditions or deny coverage entirely.9Medicare. Get Ready to Buy
So if your original six-month Medigap window has already passed and you don’t have a guaranteed-issue right, moving from Medicare Advantage back to Original Medicare during the AEP could leave you with gaps you can’t affordably fill. Confirm you can actually get the Medigap policy you’d want before you make the switch on the Medicare side.
A Practical Checklist for This Year’s AEP
- Watch for the ANOC in September and read it against your current coverage.
- Pull your EOC and check doctors, drugs, and expected total cost for next year.
- Run your prescriptions through Medicare.gov/plan-compare with the 2026 Part D out-of-pocket cap in mind.
- If you’re leaving Medicare Advantage for Original Medicare, confirm your Medigap options first.
- Submit any change so the plan receives it by December 7.
- If January arrives and the fit is wrong and you’re in a Medicare Advantage Plan, use the January 1–March 31 window to adjust.