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When can I join a Part D prescription drug plan — or switch plans if I already have coverage?

|  Medicare covers many of your health care expenses, but it doesn’t provide prescription drug coverage.

Will Medicare Part D Pay for All of My Prescription Drugs?

You have two ways to get coverage: Buy a stand-alone Part D prescription drug plan, or sign up for a Medicare Advantage plan that combines medical and drug coverage. Private insurance companies that Medicare regulates offer both types of plans. Keep in mind, you can enroll only during certain times:

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Initial enrollment period, the seven-month period that begins on the first day of the month three months before the month you turn 65 and lasts for three months after the birthday month.

Open enrollment period, which runs annually from Oct. 15 to Dec. 7, with coverage beginning Jan. 1. You also can switch to a different Part D or Medicare Advantage plan during this time.​

Medicare Advantage open enrollment period, which runs from Jan. 1 to March 31 each year. During this time, if you already have a Medicare Advantage plan, you can switch to another plan with prescription coverage. But if you switch to a Medicare Advantage health maintenance organization (HMO) or preferred provider organization (PPO) without drug coverage, make sure you have coverage from a retiree plan, Tricare or another option because you won’t be permitted to buy a separate Part D plan. Or you can leave Medicare Advantage and return to original Medicare and buy a stand-alone Part D plan. The changes take effect the first day of the following month.

Special enrollment period, which allows you to sign up for Part D outside of your initial enrollment period. To qualify, you need to meet certain criteria, such as the following:

  • If you lose health care coverage from your employer or union, you usually have up to two months to join a Part D or Medicare Advantage plan.

  • If you lose drug coverage that is considered to be at least as good as a basic Part D plan, called “creditable coverage,” then you usually have up to two months to get Part D or a Medicare Advantage plan with drug coverage. This creditable coverage may come from an employer, a retiree plan, Tricare or another source. You’ll usually receive a notice every September letting you know if your coverage is creditable.

  • If you move to a new address that isn’t in your plan’s service area, you usually have up to two months to switch to a new Part D or Medicare Advantage plan.

  • If you receive financial assistance from the Part D Extra Help program, you can switch Part D plans as much as once per calendar quarter during the first three quarters of the year.

  • If a Medicare Advantage or Part D plan in your area received a five-star rating from the Centers for Medicare & Medicaid Services (CMS), you can join that plan during the five-star special enrollment period, which lasts from Dec. 8 through Nov. 30 of the following year. It can be used once a year. Enrollment takes effect the first day of the month after the plan receives the enrollment request. 

To find out whether a five-star plan is available in your area, visit and filter the results based on star ratings. Plans with a five-star rating are marked with a special five-star icon. You can also call 800-MEDICARE (800-633-4227) to find out if any five-star plans serve your area.​

For more information about special enrollment periods, visit

You may qualify to enroll in Part D in other situations, such as if you sign up for Medicare during a general enrollment period — Jan. 1 to March 31 — because you missed your initial and special enrollment periods. If you don’t have premium-free Part A and you sign up for Part B during this time, you can get a Part D policy from April 1 to June 30. Both your Medicare and your Part D coverage will start July 1.

Keep in mind 

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If you delay and don’t have other coverage, you may have to pay a late-enrollment penalty.

Updated Feb. 17, 2022


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