You can change your Part D plan once a year during the Annual Enrollment Period, or when ready if a life event qualifies you for a Special Enrollment Period

Medicare Part D plans change their drug formularies, costs, and pharmacy networks every year. If your current plan no longer covers the medications you take, costs more than you want to pay, or your pharmacy is no longer in-network, you have the right to switch. The main window to change is the Annual Enrollment Period (AEP), which runs from October 15 to December 7 each year. Changes take effect January 1 of the following year. If you experience certain life events — such as losing employer coverage, moving out of your plan's service area, or a significant change in your income — you may be able to switch outside this window during a Special Enrollment Period.

The process itself is straightforward: you compare plans, choose a new one, and notify Medicare. You do not need to contact your old plan to leave. However, timing matters. If you miss the important date and do not have a may have access to event, you will be locked into your current plan for another full year, with a potential late enrollment penalty if you go without coverage.

Key Takeaways

  • The Annual Enrollment Period runs October 15 to December 7 each year, and any changes you make take effect January 1.
  • You can switch plans outside the enrollment period only if you have a may have access to life event, such as moving, losing employer coverage, or a major change in income.
  • Use Medicare.gov's Plan Finder tool to compare your current plan's costs against other plans in your area that cover your medications.
  • You can switch by phone, online, or by mail — you do not need to contact your old plan, and there is no fee to change.
  • If you miss the important date and have no may have access to event, you cannot change plans until the next Annual Enrollment Period.

Understanding the Annual Enrollment Period and Special Enrollment Periods

The Annual Enrollment Period is the standard window when anyone with Medicare can change their Part D plan, regardless of reason. It runs from October 15 through December 7 each calendar year. Any plan change you make during this window takes effect on January 1 of the following year. This is the only time most people can switch without a specific reason.

A Special Enrollment Period allows you to change plans outside the standard window if you meet certain conditions. may have access to events include: moving out of your plan's service area, losing employer-sponsored coverage, becoming newly may be able to access for Medicare, having a significant drop in income, or experiencing a change in your Medicaid status. If you have a may have access to event, you typically have 60 days from the date of the event to make a change. You will need to provide documentation of the event — such as a letter from your employer, proof of your move, or a notice from Social Security — when you notify Medicare.

How to Compare Plans Using Medicare.gov's Plan Finder

The fastest way to see which plans might work better for you is to use the Medicare Plan Finder tool at Medicare.gov. You will need your current medications, the pharmacies you use, and your doctors' names. The tool shows you all available Part D plans in your area, their monthly premiums, annual deductibles, copayments for each drug, and which pharmacies are in-network.

Start by entering your zip code and the medications you take. The Plan Finder will display plans ranked by estimated annual cost — your premium plus what you will pay out-of-pocket for your drugs. Pay close attention to whether your preferred pharmacy is in-network; if it is not, your copayments will be higher. Also check whether your doctors accept the plan's insurance. Some plans cover the same drug at different tiers, which changes what you pay. For example, one plan might cover your blood pressure medication as a generic (lower cost) while another covers it only as a brand-name drug (higher cost).

You can save multiple plans to compare side by side. Print or read the comparison so you have it when you are ready to enroll. The Plan Finder is updated annually and reflects the plans and costs that will be in effect on January 1.

Three Ways to Switch Your Plan

Once you have chosen a new plan, you have three options to notify Medicare. You can switch online, by phone, or by mail. There is no fee, and you do not need to contact your current plan to cancel — Medicare handles the transition automatically.

Online: Go to Medicare.gov, log into your account (or create one), and select "Change Plans" under the Part D section. Follow the prompts to confirm your new plan choice. You will receive a confirmation number when ready.

By phone: Call Medicare at 1-800-MEDICARE (1-800-633-4227). A representative will walk you through your options and enroll you in your new plan. The call is free, and you will receive a confirmation number before you hang up. TTY users can call 1-877-486-2048.

By mail: Complete the "CMS Form 588 — Change of Enrollment in a Medicare Prescription Drug Plan" and mail it to the address listed on the form. This method is slower — allow at least two weeks for processing — so use it only if you cannot reach Medicare online or by phone.

What Happens After You Switch

After you enroll in a new plan, Medicare will send you a confirmation letter within seven to ten business days. This letter confirms your new plan name, your member ID number, and your effective date (usually January 1). Keep this letter; you will need the member ID to fill prescriptions at your pharmacy starting on your effective date.

Your new plan will also send you a welcome packet with your insurance card, a complete formulary (the list of covered drugs), and pharmacy network information. Review the formulary carefully when it arrives. If your new plan does not cover a medication you expected, contact the plan's customer service number — listed on your card — to request a coverage exception or to discuss alternatives. Some exceptions can be approved within 24 hours.

Your old plan coverage ends on December 31. Do not refill prescriptions under your old plan after that date. If you have prescriptions that need refilling on or after January 1, use your new plan's pharmacy network and your new member ID.

What to Do If You Miss the Enrollment important date

If the Annual Enrollment Period ends on December 7 and you have not switched plans, you are locked into your current plan for the entire next year. You cannot change until the following October 15, unless you experience a may have access to life event.

If you miss the important date and later realize your plan no longer covers a medication you need, contact your plan's customer service to request a coverage exception. Some plans will cover an off-formulary drug if your doctor submits a request explaining why the formulary drug is not appropriate for you. This is not a may provide, but it is worth asking. You can also ask your doctor whether there is a similar medication on your plan's formulary that might work for you.

If you have a may have access to life event after the enrollment period closes — such as moving or losing employer coverage — you can still switch. Contact Medicare when ready with proof of the event. Do not wait; you have only 60 days from the date of the event to make a change.

Late Enrollment Penalties and Continuous Coverage

If you go without Part D coverage for more than 63 days in a row, Medicare will charge you a late enrollment penalty when you do enroll. The penalty is calculated based on how long you were without coverage and is added to your monthly premium for as long as you have Part D coverage. The exact amount varies by year and is set by Medicare each fall.

To avoid this penalty, make sure you have Part D coverage at all times. If you are dropping one plan to join another, your new coverage should start the same day your old coverage ends. If you are leaving Medicare Part D entirely (for example, because you have employer coverage), you must have that other coverage in place before your Part D coverage ends, or you will owe the penalty later.

Frequently Asked Questions

Can I switch Part D plans more than once a year?

No, not unless you have a may have access to life event. During the Annual Enrollment Period, you can change once. If you have a Special Enrollment Period due to a may have access to event, you can change once during that 60-day window. You cannot make multiple changes in a single year without separate may have access to events.

What if my new plan does not cover a drug my doctor prescribed?

Contact your new plan's customer service and ask for a formulary exception. Your doctor can submit a request explaining why the formulary drug will not work for you. Some plans approve exceptions within 24 hours. If the exception is denied, ask your doctor whether a similar medication on the plan's formulary might work instead.

Do I need to tell my old plan that I am leaving?

No. When you enroll in a new plan through Medicare, your old plan is automatically notified and your coverage ends on December 31 (or on your effective date if you switch during a Special Enrollment Period). You do not need to call or write your old plan.

What if I move to a different state?

Moving out of your plan's service area is a may have access to life event. You have 60 days from your move to switch plans. Use the Medicare Plan Finder and enter your new zip code to see which plans are available in your new location. Then enroll using the same three methods — online, by phone, or by mail.

Can I switch back to my old plan if I do not like my new one?

Only during the Annual Enrollment Period. If you switch in January and regret it by March, you are stuck with your new plan until October 15. The only exception is if you have a may have access to life event between now and then. Plan carefully before you switch, and use the Plan Finder to compare costs and coverage for your specific medications.