Medicare Open Enrollment Dates for 2027 Coverage

When is Medicare Open Enrollment? Medicare's Annual Open Enrollment Period (also called the Annual Election Period, or AEP) runs October 15 through December 7 every year. For 2027 coverage, that window is October 15 to December 7, 2026, and any plan you choose starts January 1, 2027.

Medicare has several enrollment windows, each with its own rules and deadlines set by the Centers for Medicare & Medicaid Services (CMS), the federal agency that runs Medicare. Missing the right one can mean late penalties, gaps, or being locked into a plan for a full year. Below is every Medicare enrollment period, when it applies, and what you can change during each. Once you know the dates, work through our Medicare Open Enrollment checklist to review your plan options for 2027.

To join a Medicare health or drug plan, you generally must have Medicare Part A and Part B, live in the plan's service area, and be a U.S. citizen or lawfully present. Have your Medicare Number and your coverage start dates handy from your Medicare card. Depending on your situation, the periods available to you may differ. Here are the main ones.

Initial Enrollment Period

This is your first window, and it is tied to your birthday, not the fall dates. It begins three months before the month you turn 65 and ends three months after, a seven-month span. During your Initial Enrollment Period you can enroll in Original Medicare (Part A and Part B), add a Medicare Advantage plan (Part C, which requires Parts A and B), and add a Medicare Part D prescription drug plan. When your coverage starts depends on when the plan receives your request.

Open Enrollment Period (the Annual Election Period)

This is the one most people mean by "open enrollment." For 2027 coverage it runs October 15 to December 7, 2026. During this window you can:

• Join, drop, or switch a Medicare Advantage plan.
• Add, drop, or change a Part D prescription drug plan.
• Move from Original Medicare to Medicare Advantage, or from Medicare Advantage back to Original Medicare.

Whatever you choose takes effect January 1, 2027. If you do nothing, your current plan renews automatically, so this is the time to check whether it still fits.

Medicare Advantage Open Enrollment Period (OEP)

If you are already in a Medicare Advantage plan, you get a second window, the Medicare Advantage Open Enrollment Period (OEP), from January 1 to March 31, 2027. During this OEP you can switch to a different Medicare Advantage plan, or drop Medicare Advantage and return to Original Medicare and add a Medicare drug plan for prescription drug coverage. You cannot use this window to move from Original Medicare into Medicare Advantage.

Special Enrollment Period (SEP)

Outside these windows, certain life events open a Special Enrollment Period (SEP) that lets you change plans during the year. Common triggers for an SEP are moving out of your plan's service area, losing employer coverage, or qualifying for Medicaid or Extra Help. Some Special Needs Plans (SNPs) for people who are dual eligible or have chronic conditions also have their own SEP rules. The length and the options available to you depend on the event.

General Enrollment Period

If you missed your Initial Enrollment Period and do not qualify for a Special Enrollment Period, you can still sign up for Part A and Part B from January 1 to March 31 each year, with coverage starting the first of the month after you enroll. A late-enrollment penalty may apply.

What you can change, and what carries over

Open enrollment is the once-a-year chance to update your Medicare health insurance without needing a special reason. Each fall, the private insurance companies that run Medicare Advantage and Part D plans can adjust premiums, drug lists, provider networks, and benefits for the coming year. Your plan mails you an Annual Notice of Change (ANOC) every September that lists the plan changes for 2027, so read this ANOC before you decide. The changes that matter most are the monthly premium, the drug formulary, your out-of-pocket costs, and whether your doctors are still in network, because those are what usually push people to switch. Medicare Advantage and Part D are private insurance, so these details vary from one plan and one insurance company to the next. If your plan still meets your needs, you can keep it and do nothing. If it no longer fits, the fall window is when you make the switch. No matter which plan you pick, you keep paying your Medicare Part B premium, which for most people is deducted from their Social Security check, and your Original Medicare Part A and Part B simply carry over into the new year.

How to compare your plan options

Knowing the dates is step one; choosing the right plan is the harder part. When you compare Medicare coverage, weigh these:

• Costs. Compare monthly premiums, deductibles, copays, and the out-of-pocket maximum so you know what you will actually pay for the year, not just the premium.
• Prescription drugs. If you take regular medications, check each plan's formulary and use its drug-cost tool to see your real out-of-pocket cost for the prescriptions you need.
• Doctors and networks. Make sure the doctors and hospitals you use are in the plan's network.
• Extra benefits. Many Medicare Advantage plans add benefits Original Medicare does not, such as dental, vision, hearing, gym memberships, or a flex card.
• Travel. If you spend part of the year in another state, confirm you are covered there.

If that feels like a lot, a licensed insurance agent can compare the plans available in your area against your doctors, drugs, and budget, at no cost to you, and explain the trade-offs in plain language. You can also get free, unbiased help from your State Health Insurance Assistance Program (SHIP).

Even if you are happy with your plan today, it is worth a look every year. Plans change, your health and prescriptions change, and the plan that was the best value last year may not be the best value for 2027. Reviewing your options during open enrollment, even for a few minutes, is how you avoid overpaying or losing coverage for a medication or doctor you need. There is no cost to compare and no obligation to switch, so the review itself carries no risk.

A note on Medigap and retiree coverage

Two other kinds of coverage sit outside the Medicare Advantage and Part D windows. Medigap (Medicare Supplement) policies help pay Original Medicare's deductibles and cost-sharing for covered services, and you can apply at any time of year, though your best pricing is during the six-month Medigap open enrollment period that starts when you are 65 and enrolled in Medicare Part B. After that window, insurers in most states can use medical underwriting to charge more or deny a policy for pre-existing conditions. Medigap does not work with Medicare Advantage. Employer or union retiree coverage can also supplement Medicare, but switching between Original Medicare and Medicare Advantage during open enrollment can affect those retiree benefits, so check with your plan before you make a change.

Next steps for Open Enrollment

Once you know the dates, work through our Medicare Open Enrollment checklist to review your options, read how to switch your plan if you want to change, and go through your plan's Annual Notice of Change to see what is different for 2027.

Common questions about Medicare Open Enrollment

When is Medicare Open Enrollment for 2027 coverage?

The Annual Enrollment Period runs October 15 to December 7, 2026. Any change you make takes effect January 1, 2027.

What can I change during Medicare Open Enrollment?

You can join, switch, or drop a Medicare Advantage plan, add or change a Part D prescription drug plan, or move between Original Medicare and Medicare Advantage.

When does my new coverage start?

January 1 of the following year. A change made during the fall 2026 window starts January 1, 2027.

What happens if I miss Medicare Open Enrollment?

Your current plan renews automatically for the new year. Your next chance to change is usually the Medicare Advantage Open Enrollment Period (January 1 to March 31) or a Special Enrollment Period if a life event qualifies you.

Is Medicare Open Enrollment the same as the AEP?

Yes. "Open Enrollment," the "Annual Enrollment Period," and the "Annual Election Period" all name the October 15 to December 7 window. It is separate from the Medicare Advantage Open Enrollment Period, which runs January 1 to March 31.

Can I switch Medicare Advantage plans after December 7?

Yes, but only if you are already in a Medicare Advantage plan. The Medicare Advantage Open Enrollment Period (January 1 to March 31) lets you make one switch or return to Original Medicare.

Do I need to do anything if I like my current plan?

No. If your plan still fits after you read the Annual Notice of Change, you can keep it and do nothing. It renews automatically for 2027.

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Want help comparing your options before December 7? A licensed Medicare Advocate will review your current plan against the plans available in your area, at no cost. Give us a call.