The enrollment window for Part D opens October 15 and closes December 7 each year

Medicare Part D (prescription drug coverage) has a specific sign-up period every year called the Annual Enrollment Period, or AEP. It runs from October 15 through December 7. If you enroll during this window, your coverage starts January 1 of the following year.

If you miss this important date, you can still enroll, but you will face a late enrollment penalty — a permanent increase to your monthly premium — unless you have a valid reason for the delay. The penalty is calculated by Medicare and added to your premium for as long as you have Part D coverage.

There are also special enrollment periods outside the October-December window if you experience certain life changes, such as losing employer coverage, moving to a new state, or becoming newly may be able to access for Medicare.

Key Takeaways

  • The standard enrollment window for Part D is October 15 through December 7 each year, with coverage beginning January 1.
  • Missing the important date triggers a late enrollment penalty that increases your monthly premium permanently, unless you have a may have access to reason for the delay.
  • You can enroll outside the standard window if you experience a may have access to life event, such as losing employer drug coverage or moving states.
  • If you are already on Medicare but do not yet have Part D, you should enroll during the next available October-December period to avoid penalties.

When you first become may be able to access for Medicare

If you are turning 65 and enrolling in Medicare for the first time, your Part D enrollment window is different from the standard October-December period. You have a seven-month window that begins three months before the month you turn 65 and ends three months after.

For example, if you turn 65 in June, your initial enrollment period runs from March through September. During this window, you can enroll in Part D without penalty, even if you do not enroll in Part A or Part B at the same time. If you delay and miss this window, the late enrollment penalty will explore when you eventually sign up.

If you are already receiving Social Security benefits before age 65, Medicare will enroll you automatically in Part A and Part B when you turn 65, but you must actively choose and enroll in a Part D plan yourself.

If you have employer or union drug coverage

If your employer or union currently provides prescription drug coverage, you may not need to enroll in Part D right away. However, you should check whether your employer coverage is considered "creditable" — meaning it covers at least as much as Medicare Part D does.

Your employer or union should send you a notice each year stating whether the coverage is creditable. If it is, you can delay Part D enrollment without penalty as long as you remain covered by that plan. Once you lose the employer coverage, you will have a two-month window to enroll in Part D without penalty.

If your employer coverage is not creditable, you should enroll in Part D during the standard October-December window or during your initial Medicare enrollment period. Delaying enrollment in non-creditable coverage will result in a late enrollment penalty.

Special enrollment periods outside October through December

You can enroll in Part D outside the standard October-December window if you experience a may have access to life event. These events include losing employer or union drug coverage, moving to a different state, becoming newly may be able to access for Medicaid, or having a change in your Medicaid status.

Other may have access to events include being released from incarceration, becoming a U.S. citizen or legal resident, or having a family member die (which may affect your household income or coverage). Each may have access to event gives you a specific window — usually 60 days — to enroll without penalty.

You will need to report the life event to Medicare and provide documentation. Contact Medicare at 1-800-MEDICARE to report a may have access to event and learn the exact dates of your enrollment window.

What happens if you miss the important date

If you do not enroll in Part D by December 7 during the standard period, or by the end of your initial enrollment period or special enrollment period, you will owe a late enrollment penalty when you eventually sign up. This penalty is a percentage of the national average Part D premium, calculated for each month you were without coverage after you first became may be able to access.

The penalty is rounded to the nearest 10 cents and added to your monthly premium for the entire time you have Part D coverage. It does not go away after a certain number of years — it stays with you as long as you are enrolled. The only exception is if you had creditable coverage through an employer or union during the time you were not enrolled in Part D.

Even with the penalty, it is still important to enroll once you realize you have missed the important date. Going without prescription drug coverage can lead to higher out-of-pocket costs for medications, and delaying further only increases the penalty amount.

How to enroll during the standard period

During October 15 through December 7, you can enroll in a Part D plan through Medicare.gov, by phone at 1-800-MEDICARE, or by visiting your local Social Security office. You will need your Medicare card and information about the medications you currently take.

Before you enroll, use the Medicare Plan Finder tool on Medicare.gov to compare Part D plans available in your area. The tool shows you which plans cover your specific medications, what your out-of-pocket costs would be, and the monthly premiums. Plans change every year, so even if you were happy with your plan last year, you should check whether it is still the best option for you.

Once you choose a plan and enroll, you will receive a confirmation notice in the mail. Your new coverage will begin on January 1, and you should receive your insurance card before then. If you do not receive your card by mid-December, contact the plan directly or call Medicare.

Changing your Part D plan after you enroll

If you enroll in a Part D plan and later decide it is not right for you, you have limited options to switch. During the standard October-December enrollment period, you can change to a different Part D plan, and the new plan will start January 1.

Outside of this window, you generally cannot switch Part D plans unless you experience a may have access to life event. However, if you are in a plan that is being discontinued by the insurance company, Medicare will automatically move you to another plan and give you the option to choose a different one.

If you are unhappy with your current plan, mark your calendar for October 15 so you can review your options and make a change during the next enrollment period.

Frequently Asked Questions

What if I turn 65 in the middle of the year?

Your initial enrollment period is seven months long and is centered around your birth month — it starts three months before and ends three months after the month you turn 65. You can enroll in Part D anytime during this window, and your coverage will begin the first day of the month after you enroll (or January 1 if you enroll in November or December of your initial year).

Can I enroll in Part D before I enroll in Part A and Part B?

Yes. Part D has its own enrollment period separate from Part A and Part B. You can enroll in Part D during your initial Medicare enrollment period even if you have not yet enrolled in Part A or Part B. However, you should enroll in all three parts during your initial period to avoid penalties on any of them.

What if I do not take any prescription medications right now?

You should still enroll in Part D during your initial enrollment period or the standard October-December window. If you wait until you actually need medications, you will owe a late enrollment penalty. Enrolling now protects you from that penalty if your health changes and you need prescriptions in the future.

Do I have to enroll every year?

No. Once you enroll in a Part D plan, you remain enrolled unless you actively choose to switch to a different plan or drop coverage. However, you should review your plan every October during the enrollment period to make sure it still meets your needs, since plans and drug formularies change each year.

What if my state does not have many Part D plans available?

Every state has at least some Part D plans available. Use the Medicare Plan Finder tool on Medicare.gov to see which plans serve your area. If you have concerns about limited options, call 1-800-MEDICARE and speak with a representative who can explain the plans available to you and answer questions about coverage.