You can switch Part D plans once a year during the annual enrollment period
Medicare Part D (prescription drug coverage) lets you change plans every year between October 15 and December 7. This window is called the Annual Enrollment Period, or AEP. During these weeks, you can drop your current plan and join a different one, with the new coverage starting January 1.
You do not have to wait for a life event or special circumstance to make this change — the annual window is open to everyone with Part D. If you miss the October 15 to December 7 important date, you are locked into your current plan for the rest of the year unless you experience a may have access to life change (such as moving to a new state, losing employer coverage, or becoming newly may be able to access for Medicare).
The reason to switch is usually cost. Drug formularies (the list of covered medications), copayments, and monthly premiums change every year. A plan that was cheapest last year may cost more this year, or it may no longer cover a drug you take. Switching lets you find the plan that fits your current medications and budget.
Key Takeaways
- You can switch Part D plans only during October 15 to December 7 each year, and the change takes effect January 1.
- Before you switch, check whether your current medications are covered under the new plan and at what cost, because formularies differ between plans.
- You can switch by calling Medicare at 1-800-MEDICARE, using Medicare.gov, or contacting the new plan directly.
- If you miss the annual window, you cannot switch unless you have a may have access to life event such as moving or losing employer coverage.
- Your old plan coverage ends December 31, so do not let prescriptions run out before the switch takes effect on January 1.
Check your medications against the new plan before you switch
The most important step is confirming that the plan you want to join covers your drugs at a price you can afford. Each Part D plan maintains its own formulary — the official list of covered medications. Two plans may both cover a drug, but one might require a higher copayment, a prior authorization from your doctor, or a step therapy (trying a cheaper drug first).
Use the Medicare Plan Finder tool at Medicare.gov. Enter your current medications, and the tool will show you which plans cover them and what you will pay out of pocket. You can also call the new plan's customer service number directly and ask whether your specific drugs are on their formulary and what the copayments are. Write down the answers so you have them in writing.
If your doctor prescribes a brand-name drug and the new plan covers only the generic version, ask your doctor whether the generic is appropriate for you. Some people do need the brand name, and your doctor can request an exception from the plan if medically necessary. This takes time, so start this conversation before you switch.
How to switch plans using Medicare.gov
Go to Medicare.gov and sign in with your Medicare account. If you do not have an account, you can create one with your Social Security number and date of birth. Click "Change Plans" or "Enroll" (the exact wording changes year to year, but it is always on the main Medicare page during the enrollment period).
The Plan Finder will show you all available Part D plans in your area, ranked by cost for your specific medications. Select the plan you want and click "Enroll." You will be asked to confirm your personal information and your choice. Once you submit, Medicare sends you a confirmation letter by mail within 7 to 10 days.
Do not rely on the online confirmation alone. Keep the confirmation letter when it arrives — you will need it to prove your coverage starts January 1. If you do not receive a letter within two weeks, call Medicare at 1-800-MEDICARE to confirm the switch went through.
Switching by phone or directly with the plan
You can call Medicare at 1-800-MEDICARE (1-800-633-4227) during the enrollment period and tell a representative you want to switch Part D plans. Have your current plan name and member ID ready, plus the name of the plan you want to join. The representative will process the switch and mail you a confirmation.
You can also call the new plan's customer service number directly and ask to enroll. The plan's phone number is on its website or in any marketing materials you have received. When you call, have your Medicare number (on your red, white, and blue Medicare card) ready. The plan will confirm your enrollment and tell you when your new member ID card will arrive.
Switching by phone takes longer than online enrollment because you depend on mail delivery for confirmation. If you choose this route, call early in the enrollment period (mid-October rather than late November) to allow time for the mail to arrive before January 1.
What happens to your old plan coverage
Your current Part D plan ends on December 31. You are covered under that plan through the last day of the year, so you can still fill prescriptions under it. Your new plan coverage begins January 1.
If you take a medication that you refill monthly, plan the timing carefully. If your refill date falls in late December, fill it under your old plan so you have medication through early January while your new plan's coverage is starting. If you wait until January 1 to refill, you may face a gap if the new plan requires prior authorization or has a different copayment that takes time to process.
Once your new plan is active, contact your pharmacy and give them your new member ID number. The pharmacy will use the new number for all future prescriptions and insurance claims.
If you realize you made a mistake after switching
If you switched plans and then discovered the new plan does not cover a medication you need, or the copayments are higher than you expected, you have limited options. You cannot switch again until the next October 15 to December 7 enrollment period — unless you experience a may have access to life event.
A may have access to life event includes moving to a new state, losing employer coverage, becoming newly may be able to access for Medicare, or having a significant change in income. If one of these applies to you, call Medicare at 1-800-MEDICARE and explain the situation. Medicare may allow you to switch outside the annual window.
If you do not have a may have access to event, contact your new plan's customer service and ask about exceptions. Some plans will cover a medication not on the formulary if your doctor requests it in writing and explains why you need that specific drug. This is not may provide, but it is worth asking.
Frequently Asked Questions
Can I switch Part D plans more than once during the enrollment period?
Yes. Between October 15 and December 7, you can switch plans as many times as you want. Only your final choice counts — that is the plan that will be active on January 1. However, switching multiple times creates confusion and delays, so choose carefully the first time.
What if I do not switch and just stay in my current plan?
Your coverage continues automatically into the next year under the same plan. Your premium, copayments, and formulary may change, so review your plan documents in September or October to see whether the changes affect you. If they do, the enrollment period gives you the chance to switch.
Do I lose coverage if I switch plans before January 1?
No. Your old plan covers you through December 31, and your new plan begins January 1. There is no gap as long as you switch during the enrollment period. If you switch outside the enrollment period without a may have access to event, you may lose coverage temporarily, so always switch during October 15 to December 7.
What if my doctor's office says my new plan will not cover my medication?
Ask your doctor to contact the plan directly and request a formulary exception in writing. The plan has 72 hours to respond. If the plan denies the exception, you can appeal. Your doctor can also suggest a covered alternative medication that may work for you. Do not assume the plan will deny the request — many exceptions are approved.
Can I switch if I have a Medigap or Medicare Advantage plan?
If you have a Medicare Advantage plan (Part C), it includes drug coverage, and you cannot have a separate Part D plan. You would switch your entire Medicare Advantage plan, not just the drug portion. If you have Original Medicare with a Medigap plan, you can switch Part D plans separately during the enrollment period.