Medicare’s Annual Enrollment Period (AEP) for 2026 runs from October 15 through December 7. During this window, Medicare beneficiaries can switch between Original Medicare and Medicare Advantage, add or drop Part D prescription drug coverage, or change to a different plan. Any changes made during this period take effect January 1, 2027. Missing the December 7 deadline means you are locked into your current coverage for the full year unless you qualify for a Special Enrollment Period.

The 2027 plan year brings updated premiums, deductibles, formularies, and provider networks across most Medicare plans. Even if you are satisfied with your current coverage, your plan’s costs and benefits may have changed. According to the Centers for Medicare & Medicaid Services, reviewing your options each year ensures your coverage still matches your health needs and budget (CMS, 2026).

What You Will Learn

This guide covers the seven key decisions Medicare beneficiaries face during the 2026 Annual Enrollment Period. You will learn how to evaluate Original Medicare versus Medicare Advantage, review prescription drug coverage, assess costs and benefits, check provider networks, consider supplemental coverage, and understand when to make changes. Each decision includes specific factors to weigh and common pitfalls to avoid before the December 7 deadline.

1. Original Medicare or Medicare Advantage

Your most fundamental choice is between Original Medicare (Parts A and B) and a Medicare Advantage plan (Part C). Original Medicare is the federal fee-for-service program. You can see any doctor or hospital that accepts Medicare nationwide, you pay 20 percent coinsurance for Part B services after meeting the deductible, and you are responsible for costs that exceed Medicare’s approved amounts unless you carry supplemental Medigap coverage.

Medicare Advantage plans are sold by private insurers approved by Medicare. These plans cover everything Original Medicare does, plus they often include prescription drug coverage (Part D), dental, vision, and hearing benefits bundled into a single monthly premium. Most Medicare Advantage plans use a network, meaning you pay less when you see in-network providers and may pay significantly more or receive no coverage out of network (except in emergencies). Medicare Advantage plans also cap your annual out-of-pocket spending, a protection Original Medicare does not provide.

Choose Original Medicare if you travel frequently, want unrestricted access to specialists, or prefer the flexibility to see any Medicare provider. Choose Medicare Advantage if you want predictable costs, extra benefits, and you are comfortable staying within a network in your local area.

2. Part D Prescription Drug Coverage

If you have Original Medicare and take prescription medications, you need a standalone Part D plan. Medicare Advantage plans often include Part D, but not always. Check whether your Medicare Advantage plan includes drug coverage or whether you need to enroll in a separate Part D policy.

Each Part D plan maintains a formulary (the list of covered drugs) and assigns medications to tiers. Generic drugs usually fall into lower-cost tiers; brand-name and specialty drugs cost more. Plans change their formularies every year. A drug covered in 2026 might move to a higher tier, require prior authorization, or be dropped entirely in 2027.

Log into the Medicare Plan Compare tool and enter every prescription you take, including dosage and frequency. The tool shows which plans cover your specific medications and estimates your total annual drug costs (premiums plus copays). A plan with a higher monthly premium might save you hundreds of dollars annually if it places your medications on lower-cost tiers.

3. Review Your Current Plan’s 2027 Changes

Every Medicare Advantage and Part D plan mails an Annual Notice of Change (ANOC) in late September. This document details what is changing for the upcoming year: premiums, deductibles, copays, covered services, prescription drug formularies, and provider networks. The Evidence of Coverage (EOC) document, also mailed in the fall, spells out the plan’s full benefits and rules for 2027.

Read both documents. If your plan is raising your premium by 15 percent, moving your prescriptions to higher tiers, or dropping your primary care doctor from the network, you have until December 7 to switch to a different plan. Many beneficiaries assume their plan stays the same year over year and discover mid-year that coverage has changed.

4. Check Provider and Pharmacy Networks

Medicare Advantage plans contract with specific doctors, hospitals, and pharmacies. A provider or pharmacy in your network this year might not be in the network next year. Before you renew your current Medicare Advantage plan or enroll in a new one, confirm your primary care doctor, specialists, preferred hospital, and usual pharmacy are all in the 2027 network.

Call the plan directly or use the plan’s online provider directory. Ask whether your doctor is accepting new patients under that plan. Some physicians remain in a network but close their panels to new Medicare Advantage enrollees, meaning you cannot see them even though they are listed as in-network.

For Part D plans (standalone or bundled into Medicare Advantage), verify your pharmacy is in the preferred network. Using a preferred pharmacy typically costs less than using a standard network pharmacy. Mail-order options can reduce costs further for maintenance medications.

5. Compare Total Annual Costs

Do not compare plans based on monthly premiums alone. Your total cost includes the Part B premium (most beneficiaries pay the standard amount, which is set annually by CMS), your plan’s monthly premium, your annual deductible, copays or coinsurance for doctor visits and hospital stays, and your out-of-pocket prescription drug spending.

Add up what you spent on healthcare in 2026 and project what you expect to spend in 2027. If you anticipate surgery, new medications, or increased use of specialists, a plan with a higher premium but lower copays and a smaller out-of-pocket maximum might cost less overall. The Medicare Plan Compare tool estimates total costs when you enter your expected healthcare use.

Medicare Advantage plans cap your annual out-of-pocket spending. Once you hit that limit, the plan pays 100 percent of covered services for the rest of the year. Original Medicare has no out-of-pocket maximum, meaning a serious illness or injury could result in unlimited 20 percent coinsurance costs unless you carry Medigap.

Read also: Medicare Advantage vs. Original Medicare: How to Choose in the United States for 2027

6. Medigap (Medicare Supplement Insurance)

Medigap policies are sold by private insurers to cover the gaps in Original Medicare: the Part A deductible, the Part B deductible, the 20 percent coinsurance, and other cost-sharing. Medigap does not work with Medicare Advantage. You can only buy Medigap if you have Original Medicare.

You cannot enroll in Medigap during the Annual Enrollment Period unless you already have a Medigap policy or you qualify for a guaranteed-issue right (such as losing employer coverage or moving out of your Medicare Advantage plan’s service area). If you are switching from Medicare Advantage back to Original Medicare and you do not qualify for guaranteed issue, insurers can deny you Medigap coverage or charge higher premiums based on your health.

If you currently have Medigap and Original Medicare, the Annual Enrollment Period is your chance to add a standalone Part D plan, drop your current Part D plan, or switch to a different Part D plan. You cannot change your Medigap plan during AEP unless your state allows year-round Medigap enrollment or you qualify for a special right.

7. When Not to Make Changes

Switching plans every year is not always the right move. If your current plan still covers your doctors, your prescriptions remain on low-cost tiers, your total costs are competitive, and the plan’s 2027 changes are minimal, staying put avoids the administrative friction of re-enrolling and re-establishing care.

Some beneficiaries switch plans chasing a lower premium only to discover the new plan’s network excludes their specialist or places their primary medication on a high tier. Run the numbers. Use the Plan Compare tool. If the savings are modest and the new plan introduces unknowns, inertia might be the correct decision.

Common Mistakes

Missing the December 7 deadline is the most costly mistake. You are locked into your current coverage for the entire year unless you qualify for a Special Enrollment Period. Set a reminder for late November to finalize your decision.

Choosing a plan based solely on premium is another frequent error. A zero-dollar premium Medicare Advantage plan might carry high copays, a restrictive network, or a deductible that makes it more expensive than a plan with a modest monthly premium.

Failing to verify provider and pharmacy networks before enrolling is the third most common pitfall. Beneficiaries assume their doctor participates in a new plan and discover in January that the doctor is out of network or not accepting new patients under that plan.

Frequently Asked Questions

Can I switch from Medicare Advantage back to Original Medicare during the Annual Enrollment Period?

Yes. The Annual Enrollment Period allows you to move from Medicare Advantage to Original Medicare. If you switch back, you will need to enroll in a standalone Part D plan if you want prescription drug coverage, and you may want Medigap coverage. Medigap insurers can deny you or charge higher premiums based on your health unless you qualify for a guaranteed-issue right.

What happens if I do nothing during the Annual Enrollment Period?

Your current coverage continues unchanged into 2027. If you have Original Medicare, you keep Original Medicare. If you have a Medicare Advantage or Part D plan, you stay in that plan with its 2027 premiums, benefits, and networks as described in your Annual Notice of Change.

Can I make changes after December 7?

The Medicare Advantage Open Enrollment Period runs from January 1 through March 31 each year. During this period, you can switch from one Medicare Advantage plan to another or drop your Medicare Advantage plan and return to Original Medicare. You can also enroll in a Part D plan during this window if you dropped Medicare Advantage. You cannot join a Medicare Advantage plan for the first time during this period unless you are newly eligible for Medicare.

Take Action Before December 7

Review your Annual Notice of Change, enter your prescriptions into the Plan Compare tool, confirm your doctors and pharmacies are in the 2027 network, and calculate your total projected costs for each plan option. If your current plan still meets your needs and remains cost-competitive, you can stay enrolled without taking action. If you find a better option, enroll by December 7 so your new coverage starts January 1, 2027.

This article provides general educational information about the 2026 Medicare Annual Enrollment Period and is not personalized health, insurance, or financial advice. Medicare plans, costs, networks, and formularies vary by location and change annually. Verify current plan details with the Centers for Medicare & Medicaid Services at Medicare.gov or call 1-800-MEDICARE. Consult a licensed insurance agent or a State Health Insurance Assistance Program (SHIP) counselor for guidance on your individual situation.