Medicare Open Enrollment runs from October 15 to December 7, 2025

Open Enrollment is the one time each year when you can change your Medicare coverage without a penalty. In 2025, that window opens on October 15 and closes on December 7. Any changes you make during this period take effect on January 1, 2026.

If you miss the December 7 important date, you cannot switch plans until the next Open Enrollment period in October 2026 — unless you have a may have access to life event like losing employer coverage, moving to a new state, or getting married. Even then, you typically have only 60 days from the event to make a change.

Open Enrollment applies whether you have Original Medicare with a Medigap or Part D plan, a Medicare Advantage plan, or any combination. You can switch between any of these options during this window.

Key Takeaways

  • Open Enrollment for 2025 runs October 15 through December 7, with changes taking effect January 1, 2026.
  • You can switch from Original Medicare to Medicare Advantage, from Medicare Advantage to Original Medicare, or change to a different plan within the same category.
  • Missing the important date means you cannot change plans until October 2026, except in cases of may have access to life events.
  • Plan costs, drug coverage, and provider networks change every year, so reviewing your current plan against new options is worth your time.
  • Medicare sends a notice in the mail before Open Enrollment begins, and you can compare plans on Medicare.gov or by calling 1-800-MEDICARE.

What you can change during Open Enrollment

During Open Enrollment, you have four main options. You can switch from Original Medicare to a Medicare Advantage plan. You can switch from Medicare Advantage back to Original Medicare. You can change from one Medicare Advantage plan to a different Medicare Advantage plan. Or you can change your prescription drug plan (Part D) or your Medigap supplemental insurance if you have Original Medicare.

You cannot, however, switch Medigap plans during Open Enrollment unless you are newly may be able to access for Medicare or within six months of first enrolling in Part B. If you already have a Medigap policy and want to change it, you will need to contact your insurance company directly — they may or may not allow the switch depending on your health and their underwriting rules.

The same restriction applies to Medicare Part D plans if you currently have one. You can drop it and pick a new one during Open Enrollment, but you cannot switch between two existing Part D plans outside of this window.

How to compare plans before Open Enrollment

You do not have to wait until October 15 to start looking. Medicare.gov has a plan comparison tool that is updated each year with 2025 pricing and coverage. You can enter your medications, doctors, and hospitals to see which plans cover them and what your out-of-pocket costs would be.

In September, Medicare mails every person with Medicare a notice called the "Annual Notice of Change" or "Important Notice About Your Coverage." This document lists what is changing in your current plan for 2025 — premium increases, deductible changes, or shifts in which drugs or doctors are covered. Read it carefully, because it tells you whether your plan is still a good fit.

You can also call 1-800-MEDICARE to speak with a representative who can walk you through your options. They cannot tell you which plan to pick, but they can explain the differences and help you understand what each plan covers.

When to switch from Medicare Advantage to Original Medicare

Medicare Advantage plans have lower premiums than Original Medicare with a Medigap policy, but they limit which doctors you can see and often require prior approval for specialist visits or procedures. If your doctor is leaving your plan's network, or if you are moving to a state where your plan does not operate, Open Enrollment is your chance to switch to Original Medicare without being denied for pre-existing conditions.

Original Medicare covers you anywhere in the United States and does not require referrals. The trade-off is that you pay a 20 percent coinsurance on most services after you meet your deductible, and you have no annual out-of-pocket maximum. Many people add a Medigap policy to cover those costs, but Medigap premiums are separate from your Medicare premium.

If you are considering this switch, compare the total cost: your Medicare Part B premium plus your Medigap premium and deductible against your current Medicare Advantage premium and out-of-pocket limits. The math often favors Original Medicare if you see many doctors or specialists, but not always.

When to switch from Original Medicare to Medicare Advantage

Medicare Advantage plans bundle Part A, Part B, and usually Part D into one monthly premium, which is often lower than paying for Original Medicare, a Medigap policy, and a separate Part D plan. If your costs are high under Original Medicare, or if you want a plan that covers dental, vision, or hearing aids, Medicare Advantage may save you money.

The catch is that Medicare Advantage plans use networks. Your doctor may not be in the plan, or may be leaving the network next year. Before you switch, call the plan and confirm that your current doctors are in-network and that your medications are covered at a tier you can afford.

If you switch to Medicare Advantage during Open Enrollment and then change your mind, you have one chance to switch back to Original Medicare during the Medicare Advantage Disenrollment Period, which runs January 1 to February 14, 2026. After that, you are locked in until the next Open Enrollment.

Prescription drug coverage changes for 2025

If you take medications, your Part D plan may have changed the tier (cost level) of your drugs, dropped a drug from its formulary, or raised its premium. Even if you stay with the same plan, your out-of-pocket costs can shift significantly from year to year.

During Open Enrollment, you can switch to a different Part D plan if your current plan no longer covers your medications at an affordable price. Use the Medicare.gov plan finder and enter each of your medications to see which plans cover them and what you would pay. A plan with a higher premium might have lower copays for your specific drugs, so compare the total cost, not just the monthly premium.

If you do not have Part D coverage and you go without prescription drug insurance for more than 63 days in a row, you will owe a late enrollment penalty for as long as you have Medicare. That penalty is added to your Part D premium each month, so it pays to enroll during Open Enrollment even if you do not take many medications now.

Important dates and important date for 2025

Open Enrollment begins October 15, 2025, and ends December 7, 2025. Your new coverage takes effect January 1, 2026. If you enroll after December 7, your coverage will not start until the following month, so you will have a gap in coverage.

Medicare mails the Annual Notice of Change in September, usually by mid-month. If you do not receive yours by late September, call 1-800-MEDICARE to request one or view it online at Medicare.gov.

If you have a may have access to life event — such as losing employer coverage, moving out of state, getting married, or having a baby — you have 60 days from the event to make a change outside of Open Enrollment. You will need to report the event to Medicare and provide proof, such as a letter from your employer or a marriage certificate.

Frequently Asked Questions

What happens if I do not make any changes during Open Enrollment?

Your current plan automatically continues into 2026 with whatever changes the plan made to its premiums, deductibles, and coverage. You will not lose coverage, but your costs may go up and your coverage may change. That is why reviewing your plan each year matters.

Can I switch plans more than once during Open Enrollment?

Yes. You can change your mind as many times as you want between October 15 and December 7. Only your last selection counts. Medicare processes the final change you make by the December 7 important date.

Do I have to enroll in Part D if I do not take any medications?

You do not have to, but if you go without Part D coverage for more than 63 days and then enroll later, you will pay a permanent late enrollment penalty. If you think you might need medications in the future, it is cheaper to enroll now and pay the premium than to wait and pay the penalty.

What if my doctor is leaving my Medicare Advantage plan?

That is a may have access to event that allows you to switch plans outside of Open Enrollment. Contact your plan or call 1-800-MEDICARE as soon as you learn your doctor is leaving, and ask about your options. You may have 60 days to make a change.

Can I get help choosing a plan?

Yes. You can call 1-800-MEDICARE to speak with a representative, use the plan comparison tool at Medicare.gov, or contact your State Health Insurance information Program (SHIP), which offers free counseling. SHIP can be reached through the Eldercare Locator at 1-800-677-1116.