What Open Enrollment Means for Your Medicare Coverage

Open Enrollment for Medicare is a set window each year when you can change your coverage without penalty — switch plans, drop coverage, or sign up for the first time. For most people with Medicare, this window runs from October 15 to December 7 each year. During these weeks, Medicare Part C (Advantage plans) and Part D (prescription drug coverage) let you move to a different plan or return to Original Medicare, and the changes take effect January 1.

Outside Open Enrollment, you cannot switch plans unless you have a may have access to life event — moving to a new state, losing employer coverage, getting married, or a similar change. Knowing when Open Enrollment happens and what you can actually change during it saves you from being locked into a plan that no longer fits your needs or budget.

Key Takeaways

  • Open Enrollment runs October 15 to December 7 each year, and changes take effect January 1 of the following year.
  • You can switch between Medicare Advantage plans, return to Original Medicare with a Medigap or Part D plan, or drop Part D coverage entirely during this window.
  • If you miss Open Enrollment and do not have a may have access to life event, you cannot change plans until the next October.
  • Your current plan's costs, coverage, and provider networks often change year to year, so reviewing your options each fall is worth the time.
  • You do not need to do anything if you are happy with your current plan — it will renew automatically on January 1.

The Exact Dates and What Changes Take Effect When

Open Enrollment for Medicare Part C and Part D runs from October 15 through December 7 each calendar year. Any changes you make during this period take effect on January 1 of the next year. This means if you switch from one Advantage plan to another in November, your new plan's coverage and costs begin on January 1, and your old plan ends.

The timing matters because your current plan remains in effect through December 31, even after you have chosen a new one. If you need prescriptions filled or medical care in late December, use your current plan's coverage. Starting January 1, you are covered under whichever plan you selected during Open Enrollment.

If you do nothing during Open Enrollment, your current plan automatically renews for the next year. However, the plan's premiums, deductibles, copays, and covered drugs often change on January 1, so inaction does not mean your costs stay the same.

What You Can Change During Open Enrollment

During Open Enrollment, you can switch from one Medicare Advantage plan to another Advantage plan offered in your area. You can also switch from Advantage back to Original Medicare, though this choice comes with an important caveat: if you return to Original Medicare, you can only add a Medigap policy if you are still within your initial Medigap enrollment window (usually six months from when you first turned 65 and enrolled in Part B). After that window closes, insurers can deny you or charge more based on your health history.

For Part D prescription drug coverage, you can switch to a different Part D plan or drop Part D altogether if you have other creditable coverage (such as coverage through a current or former employer). If you drop Part D and later want to rejoin without creditable coverage, you may pay a penalty for each month you were without it.

You cannot change your Part A or Part B coverage during Open Enrollment — those choices are made when you first turn 65 or become may be able to access for Medicare. You also cannot add or drop Medigap coverage during Open Enrollment unless you are in your initial enrollment window; outside that window, Medigap has its own limited enrollment periods tied to life events.

Why Your Plan's Details Change Every Year

Even if you love your current plan, its costs and coverage shift each January. Insurance companies adjust premiums based on claims data and expected medical costs. They also change which doctors and hospitals are in-network, which drugs are covered under Part D, and how much you pay out of pocket for each service.

A plan that was affordable in 2024 might cost significantly more in 2025. A specialist you see regularly might leave the network. A medication you take daily might move to a higher cost tier. These changes happen to thousands of plans every year, which is why Medicare sends you a notice in the fall listing what is changing in your plan for the coming year.

Reviewing your plan each October — even if you have been with it for years — takes about an hour and can save you hundreds of dollars or prevent coverage gaps. The Medicare Plan Finder tool on Medicare.gov lets you compare plans side by side based on your doctors, prescriptions, and expected care.

What Happens If You Miss Open Enrollment

If Open Enrollment ends on December 7 and you have not made a change, you are locked into your current plan for the entire next year. You cannot switch to a different Advantage plan, return to Original Medicare, or change your Part D coverage until the following October 15.

The only exception is a may have access to life event. These include moving to a new state or county, losing employer-sponsored coverage, getting married or divorced, becoming a U.S. citizen, or experiencing a significant change in income. If one of these events happens to you, you have a limited window — usually 60 days — to make changes outside of Open Enrollment. You will need to contact Medicare or your plan directly to report the event and request a Special Enrollment Period.

Missing Open Enrollment is not a permanent mistake, but it does mean waiting until October to make changes. If your plan becomes unaffordable or stops covering your doctors in January, you cannot switch until fall.

How to Review and Compare Your Options

Start by reading the Annual Notice of Change that your current plan mails to you in September or early October. This document lists what is changing in your plan for the next year — new premiums, deductible changes, formulary updates for prescriptions, and network changes. If nothing major is changing and your costs are stable, you may decide to stay.

If you want to explore other plans, use the Medicare Plan Finder at Medicare.gov. Enter your zip code, current medications, and preferred doctors and hospitals. The tool shows you all available Advantage and Part D plans in your area, their costs, and how well they cover your needs. You can compare plans side by side and see estimated out-of-pocket costs for your specific situation.

You can also call Medicare directly at 1-800-MEDICARE (1-800-633-4227) to speak with a representative who can walk you through your options. Many states also run State Health Insurance information Programs (SHIPs) that offer free, one-on-one counseling about Medicare plans. Your state's SHIP can be found through the Eldercare Locator at eldercare.acl.gov.

Making Your Change Before the important date

Once you have decided on a new plan, you have several ways to enroll. You can enroll online through Medicare.gov, by phone at 1-800-MEDICARE, or directly through the insurance company offering the plan you want. Online enrollment is usually fastest — you can complete it in 10 to 15 minutes and receive confirmation when ready.

If you are switching from one Advantage plan to another, you do not need to contact your current plan to cancel; the new plan enrollment automatically ends your old coverage on December 31. However, if you are switching from Advantage to Original Medicare, you may want to contact your Advantage plan to confirm the cancellation, though it is not required.

Make your change before December 7 at 11:59 p.m. Eastern Time. Enrollments submitted after that important date will not take effect on January 1. If you miss the important date, you will need to wait for the next Open Enrollment period in October, unless you experience a may have access to life event.

Frequently Asked Questions

Can I switch plans more than once during Open Enrollment?

Yes. You can change your mind and switch to a different plan as many times as you want during Open Enrollment, as long as each change is submitted before the December 7 important date. Only your final enrollment counts, and that is the plan you will have starting January 1.

What if I move to a different state during Open Enrollment?

Moving to a new state is a may have access to life event, which means you can change plans outside of Open Enrollment. Contact Medicare within 60 days of your move to report the change and request a Special Enrollment Period. You will then have time to find a plan available in your new state.

Do I have to choose a new plan, or can I keep the same one?

You do not have to do anything. If you are satisfied with your current plan, it will automatically renew on January 1 with whatever changes the company has made to premiums, deductibles, and coverage. You only need to act if you want to switch.

What if my doctor is no longer in my plan's network next year?

If your doctor leaves your plan's network, that is considered a may have access to life event in many cases, allowing you to change plans outside of Open Enrollment. Contact your plan or Medicare to report the change and ask whether you are may be able to access for a Special Enrollment Period.

Can I go back to Original Medicare if I chose an Advantage plan?

Yes, during Open Enrollment you can switch from Advantage back to Original Medicare. However, you can only add a Medigap policy at that time if you are still within your initial Medigap enrollment window (usually six months from when you first enrolled in Part B). If that window has closed, you may not be able to get Medigap coverage, or you may pay higher premiums.