How to Sign Up for Medicare Part D Coverage

Medicare Part D enrollment happens during specific windows each year, and the process differs depending on whether you are new to Medicare or already covered

You sign up for Medicare Part D (prescription drug coverage) through Medicare directly — either online at Medicare.gov, by phone, or in person at a Social Security office. The timing matters: you have a seven-week window when you first turn 65 or become may be able to access, and a second chance every year during the Annual Enrollment Period from October 15 to December 7. If you miss these windows, you may pay a penalty for every month you go without coverage.

The process itself is straightforward: you choose a plan from the list of Part D plans available in your area, confirm your prescription drugs are covered under that plan's formulary, and complete the enrollment. Most people finish in 10 to 15 minutes online. The coverage then starts the first day of the following month.

Key Takeaways

You enroll in Part D through Medicare.gov, by calling 1-800-MEDICARE, or at your local Social Security office — not through your doctor or pharmacy.
Your initial enrollment window is seven weeks: it starts three months before the month you turn 65 and ends three months after.
The Annual Enrollment Period runs October 15 to December 7 each year, and coverage changes take effect January 1.
You must check your specific drugs against each plan's formulary before enrolling, because coverage and costs vary widely between plans.
Missing your enrollment window without other coverage triggers a late penalty that stays on your premiums permanently.

Your initial enrollment window: the seven-week period when you first may have access to

When you turn 65, your Part D enrollment window opens three months before that birthday and closes three months after. For example, if you turn 65 in June, you can enroll from March through September. This seven-week window applies whether you are turning 65 or becoming may be able to access for Medicare earlier due to disability or end-stage renal disease.

If you are already on Medicare but have not yet chosen Part D coverage, you are still in your initial enrollment period until three months after the month you first became may be able to access. Once that window closes, you can only enroll during the Annual Enrollment Period (October 15 to December 7) or if you experience a may have access to life event, such as losing employer coverage or moving to a different state.

The Annual Enrollment Period: your yearly chance to switch plans

Every year from October 15 through December 7, you can enroll in a new Part D plan, switch to a different plan, or drop coverage entirely. This is the main enrollment window for people already on Medicare. Any changes you make during this period take effect on January 1 of the following year.

You do not have to change plans every year — if you are happy with your current coverage and costs, you can do nothing and your plan continues. However, formularies and premiums change annually, so it is worth reviewing your plan each October to confirm your drugs are still covered at the same cost.

How to enroll: the three ways to sign up

Online at Medicare.gov is the fastest route. Go to Medicare.gov/plan-compare, enter your zip code, select the plans available in your area, and review which ones cover your prescriptions. Once you choose a plan, you can complete enrollment right there. You will need your Medicare number (on your red, white, and blue Medicare card) and a list of your current medications.

By phone, call 1-800-MEDICARE (1-800-633-4227). A representative will walk you through available plans, help you compare costs for your specific drugs, and enroll you over the phone. The call usually takes 20 to 30 minutes. TTY users can call 1-877-486-2048.

In person at your local Social Security office. You can walk in during business hours or call ahead to schedule an appointment. Bring your Medicare card and a list of your medications. A representative will help you review plans and complete the enrollment form.

Checking your drugs before you enroll

Before you choose a plan, use the Medicare Plan Finder tool on Medicare.gov to see which of your medications are covered under each plan and what you will pay. Enter each drug name, strength, and dosage — the tool will show you the monthly premium, deductible, copay or coinsurance for each drug, and any restrictions (such as prior authorization or quantity limits).

Plans vary dramatically in what they cover. One plan might cover your blood pressure medication with a $5 copay, while another charges $50 or does not cover it at all. Spending 10 minutes comparing plans can save you hundreds of dollars a year. If your drugs are not listed, call the plan directly or check its website formulary — the complete list of covered drugs.

If a drug you need is not covered by any plan in your area, you can request an exception from the plan you choose. This process takes a few days to a few weeks, and the plan may approve it, deny it, or approve it with conditions (such as trying a cheaper drug first).

What happens after you enroll

Once you complete enrollment, Medicare sends you a confirmation letter within two weeks. Your coverage starts on the first day of the following month. For example, if you enroll on March 15, your coverage begins April 1. You will receive your insurance card in the mail before your coverage starts.

When you pick up a prescription, show your Part D card at the pharmacy. The pharmacy will verify your coverage and tell you what you owe. If there is a problem — such as the drug not being covered or a prior authorization being required — the pharmacy will contact the plan on your behalf, or you can call the plan's customer service number on the back of your card.

Late enrollment penalties and what they cost

If you do not enroll in Part D during your initial seven-week window or during the Annual Enrollment Period, and you do not have other creditable prescription drug coverage (such as employer coverage or TRICARE), you will owe a late enrollment penalty. This penalty is calculated as 1% of the national average Part D premium for each full month you were without coverage. The penalty is added to your premium permanently — it does not go away after a certain time.

The national average premium changes each year, so the penalty amount changes too. In 2024, the average was around $34 per month, meaning a penalty of roughly $0.34 per month of delay. If you went without coverage for two years, your penalty would be roughly $8 per month for life. The only way to avoid or remove the penalty is to have had other creditable coverage during the gap.

may have access to life events that let you enroll outside the regular windows

If you experience certain life changes, you can enroll in Part D outside the regular enrollment periods. These may have access to life events include losing employer or union coverage, moving to a different state, getting married or divorced, or having a significant change in income. You typically have 60 days from the event to enroll.

To report a may have access to life event, call 1-800-MEDICARE or visit Medicare.gov. Have details about the event ready — such as the date your employer coverage ended or your new address. Medicare will verify the event and give you a new enrollment window if you may have access to.

Frequently Asked Questions

Can I enroll in Part D if I am still working and have employer drug coverage?

Yes, but you do not have to. If your employer coverage is as good as or better than Part D, you can skip Part D and stay on your employer plan. When you eventually retire and lose that coverage, you will have 60 days to enroll in Part D without a late penalty. Ask your employer's benefits office whether your coverage is considered "creditable" — if it is, you are protected from penalties.

What if I want to switch Part D plans in the middle of the year?

You cannot switch plans outside the Annual Enrollment Period (October 15 to December 7) unless you have a may have access to life event, such as moving to a new state or losing employer coverage. If your circumstances change, call 1-800-MEDICARE to see whether you may have access to for a special enrollment period.

Do I have to choose a plan with the lowest premium?

No. Choose the plan that covers your specific drugs at the lowest total cost to you — that includes the premium, deductible, copays, and coinsurance. A plan with a higher premium might cost less overall if it covers your expensive medications with lower copays.

What if my doctor prescribes a new drug that is not covered by my plan?

Contact your Part D plan and ask for a coverage exception. The plan will review the request, usually within 24 to 72 hours. If denied, you can appeal. In the meantime, ask your doctor whether a covered alternative drug would work, or whether the plan requires you to try a cheaper drug first before approving the one your doctor prescribed.

Can I enroll in Part D online if I do not have internet access?

Yes. Call 1-800-MEDICARE and a representative will enroll you by phone, or visit your local Social Security office in person. Both options are free and take about 20 to 30 minutes.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.