How to Sign Up for Medicare Part D Coverage

When and where to sign up for Part D

You sign up for Medicare Part D (prescription drug coverage) through insurance companies, not through Medicare directly. You choose a Part D plan offered by a private insurer, and that company handles your enrollment. The easiest way to browse plans and enroll is through Medicare.gov, where you can compare what each plan covers and costs, then select one and complete the enrollment right there.

Timing matters. If you have Part A or Part B, your Initial Enrollment Period is the seven-month window that starts three months before the month you turn 65 and ends three months after. If you miss this window, you can still enroll during the Annual Enrollment Period, which runs October 15 through December 7 each year. Coverage begins January 1 of the following year.

If you delay enrolling in Part D without having other drug coverage (like an employer plan), you may owe a late enrollment penalty — an extra amount added to your premium each month for as long as you have Part D. The penalty amount varies by year and is calculated based on how many months you went without coverage.

Key Takeaways

You enroll in Part D through private insurance companies using Medicare.gov, not by calling Medicare.
Your Initial Enrollment Period is seven months long, centered on the month you turn 65, and missing it triggers a permanent penalty.
Part D plans vary widely in cost, deductibles, and which drugs they cover, so comparing plans before you choose matters.
You can change Part D plans once per year during the Annual Enrollment Period (October 15 to December 7).
If you have drug coverage through an employer or union, you may not need Part D right away, but you should verify your coverage is "creditable."

Steps to enroll through Medicare.gov

Go to Medicare.gov and log in with your username and password, or create an account if you do not have one. You will need your Social Security number and email address. Once logged in, look for "Find Care Providers & Suppliers" or "Prescription Drug Plans" — the exact link name changes, but it will be in the main navigation.

Enter your zip code and the medications you currently take (or leave it blank if you prefer to browse first). The site will show you all Part D plans available in your area, ranked by estimated yearly cost. Click on each plan to see the full details: the monthly premium, annual deductible, copays for different drug tiers, and whether your specific medications are covered.

When you find a plan you want, click "Enroll" on that plan's page. You will answer questions about your income (to see if you may have access to for a subsidy that lowers your costs), confirm your address, and review your enrollment summary. Submit the form, and you will receive a confirmation number. Your coverage begins on the first day of the following month if you enroll by the 15th; if you enroll after the 15th, coverage starts the first of the month after that.

What information you need before you start

Have your current medications list ready — the brand names and dosages. If you do not know the exact dosages, you can call your pharmacy or doctor's office and ask them to read it to you. You do not need to enter every medication, but listing the ones you take regularly helps you see which plans cover them and at what cost.

You will also need your income information if you think you might may have access to for a Low-Income Subsidy (LIS) or Extra Help, which are programs that reduce your Part D costs based on what you earn. Have your most recent tax return or Social Security statement handy so you can answer questions about your household income and assets.

If you are already on Medicare, you will need your Medicare number (on your red, white, and blue Medicare card). If you are not yet on Medicare but are turning 65 soon, you can still create an account and explore plans before your enrollment period opens.

Understanding plan differences and costs

Part D plans are not all the same. Each plan sets its own monthly premium, annual deductible, and copays. Some plans have a low premium but a high deductible; others have a higher premium but cover more drugs from the start. The "best" plan depends on which drugs you take and how often you refill them.

Pay attention to the formulary — the list of drugs each plan covers. If a medication you need is not on the formulary, you may have to pay out of pocket or ask your doctor about a covered alternative. Some plans cover brand-name drugs more generously than others; some require you to try a generic version first before they will cover the brand name.

Also check whether your pharmacy is in the plan's network. Most Part D plans work with large pharmacy chains like CVS, Walgreens, and Rite Aid, but some have narrower networks. If you use a specialty pharmacy or a small local one, confirm it is included before you enroll.

If you have other drug coverage

If you have prescription drug coverage through a current or former employer, a union, or the Veterans Health Administration, you may not need Part D right away. However, you should check whether that coverage is creditable — meaning it is at least as good as Part D. Your employer or plan administrator can tell you this, usually in a letter sent in October or November each year.

If your coverage is creditable, you can delay enrolling in Part D without facing a late enrollment penalty. But if your coverage ends, you have 63 days to enroll in Part D without penalty. If you wait longer than 63 days, the penalty applies.

If you are not sure whether your coverage is creditable, contact your plan administrator or call Medicare at 1-800-MEDICARE (1-800-633-4227) and ask. It is worth confirming before you turn down Part D, because the penalty is permanent.

Changing your Part D plan

You are not locked into your first choice. During the Annual Enrollment Period (October 15 to December 7), you can switch to a different Part D plan, and the new coverage begins January 1. You can also switch if you may have access to for a Special Enrollment Period — for example, if you lose your job, move to a new state, or experience another major life change.

If you want to change plans, go back to Medicare.gov during the enrollment window, compare plans again (your medication list and costs may have changed), and enroll in the new plan. Your old plan will end automatically on December 31.

Getting help if you get stuck

If you do not have internet access or prefer to enroll by phone, call Medicare at 1-800-MEDICARE (1-800-633-4227). A representative can walk you through the plan options and help you enroll over the phone. The call is free, and representatives are available 24 hours a day, seven days a week.

You can also visit your local Social Security office or a State Health Insurance information Program (SHIP) office in person. SHIP counselors are trained to help older adults understand Part D and can sit with you while you compare plans. To find your local SHIP, search "SHIP" plus your state name online, or call 1-800-MEDICARE and ask for the number.

Frequently Asked Questions

What happens if I miss my Initial Enrollment Period?

You can still enroll during the Annual Enrollment Period each October through December, but you will owe a late enrollment penalty on top of your monthly premium for as long as you have Part D. The penalty is permanent, even if you switch plans later. The only exception is if you had other creditable drug coverage during the time you were not enrolled in Part D.

Can I enroll in Part D if I do not have Part A or Part B yet?

Yes. If you are not yet on Medicare but are turning 65 soon, you can enroll in Part D during your Initial Enrollment Period, which starts three months before the month you turn 65. Your Part D coverage can begin before your Part A or Part B coverage does.

Do I have to choose a plan every year?

No. If you do not make a change during the Annual Enrollment Period, your current plan will automatically renew for the next year. However, plans change their premiums and formularies each year, so it is a good idea to review your plan at least once a year to make sure it still fits your needs and budget.

What if my medication is not covered by the plan I chose?

You can ask your doctor about a covered alternative, or you can request an exception from the insurance company. Some plans will cover a non-formulary drug if your doctor writes a letter explaining why you need that specific medication. You can also switch to a different Part D plan during the Annual Enrollment Period.

How much does Part D cost?

Part D premiums vary by plan and location. Some plans cost less than $10 per month; others cost $50 or more. You will also pay a deductible (usually $0 to $500) and copays when you fill prescriptions. The exact costs depend on which plan you choose and whether you may have access to for a subsidy based on your income.

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.