Your Medicare Enrollment Checklist: When to Sign Up and What You Need

When you turn 65, you have a three-month window to sign up for Medicare without paying a penalty for the rest of your life

Your enrollment window opens three months before the month you turn 65 and closes three months after. If you miss it, you will pay a permanent surcharge on your premiums — 10% more per year for each 12 months you delayed. The only exception is if you or your spouse still work and have health coverage through that job; in that case, you can delay without penalty, but you must sign up within eight months of losing that coverage or retiring, whichever comes first.

You do not have to wait until your birthday month to enroll. Starting three months early means you can spread the steps across a longer timeline and avoid the rush. Most people enroll online through Medicare.gov, but you can also call 1-800-MEDICARE or visit your local Social Security office in person.

Key Takeaways

• Your enrollment window is seven months long: three months before your 65th birthday, the month you turn 65, and three months after.
• You will need your Social Security number, birth date, citizenship or immigration status, and information about any current health coverage.
• Original Medicare (Part A and Part B) requires you to choose whether to enroll in Part D (prescription drug coverage) at the same time to avoid a lifetime penalty.
• If you choose a Medicare Advantage plan instead, it includes drug coverage, and you do not need to enroll in Part D separately.
• Enrollment takes about 10 minutes online, and coverage can start as early as the first day of the month you turn 65.

Gather these documents before you start

Have your Social Security number, date of birth, and citizenship information ready. You will also need details about any health coverage you currently have — the name of your employer or insurance company, your policy number, and whether coverage will end when you turn 65 or if you are still working.

If you have worked for the federal government, railroad, or certain other employers with their own retirement systems, gather that information too. Some people are covered by these systems instead of Social Security, and Medicare needs to know which one applies to you.

Write down the names and dosages of all medications you take. If you are enrolling in a plan that includes prescription drug coverage (Part D or Medicare Advantage), the plan will use this list to tell you whether your drugs are covered and what you will pay.

Decide between Original Medicare and Medicare Advantage

Original Medicare is two parts: Part A covers hospital stays, and Part B covers doctor visits and outpatient care. You pay a monthly premium for Part B (the amount varies by income), and you pay a share of costs when you use care. Most people do not pay a premium for Part A if they or their spouse paid Medicare taxes for at least 10 years.

Medicare Advantage is an alternative run by private insurance companies. It includes Part A, Part B, and prescription drug coverage all in one plan. You usually pay a lower or zero monthly premium, but you may pay more when you use care, and your choice of doctors and hospitals may be limited. Advantage plans change their networks and costs every year, so what works one year may not work the next.

If you choose Original Medicare, you must also enroll in Part D (prescription drug coverage) during your initial enrollment window. If you do not, you will pay a 1% surcharge on your Part D premium for every month you delayed, for as long as you have Part D. If you choose Medicare Advantage, Part D is included and you do not enroll separately.

Step-by-step: enrolling online through Medicare.gov

Go to Medicare.gov and click "Sign Up for Medicare." You will create a login or sign in with an existing account. The form asks for your name, date of birth, Social Security number, and citizenship status. It takes about five minutes.

Next, you choose your coverage. If you want Original Medicare, you confirm Part A and Part B. Then you move to Part D and choose a prescription drug plan. Medicare shows you plans available in your zip code, ranked by cost for your specific medications. Compare the monthly premium, the annual deductible, and what you pay per prescription.

If you want Medicare Advantage, you search plans by zip code and compare monthly premiums, deductibles, and which doctors and hospitals are in the network. You can enroll in only one plan at a time. Once you submit, you receive a confirmation number — save this.

Coverage starts on the first day of the month you turn 65, or the first day of the following month if you enroll after the 15th. You will receive your Medicare card in the mail within two weeks.

If you are still working or have employer coverage

If you or your spouse are still working and have health coverage through that job, you can delay Medicare Part B without penalty. Part A (hospital coverage) is usually still worth taking at 65 because it has no premium for most people. You must enroll in Part B within eight months of losing your job or retiring, whichever comes first.

Tell Medicare that you have employer coverage when you enroll. You will need your employer's name and the date your coverage ends. This protects you from the late-enrollment penalty if you enroll in Part B after your window closes.

If your employer has 20 or more employees, your employer's health plan pays first, and Medicare pays second. If your employer has fewer than 20 employees, Medicare pays first. Either way, you still need to enroll in Medicare to have coverage.

Enrolling by phone or in person

Call 1-800-MEDICARE (1-800-633-4227) Monday through Friday, 8 a.m. to 8 p.m. Eastern time. A representative will walk you through the same questions as the online form. The call usually takes 15 to 20 minutes. You will receive a confirmation number and your Medicare card will arrive by mail.

To enroll in person, visit your local Social Security office. Bring your Social Security card, proof of citizenship (passport, birth certificate, or naturalization papers), and proof of residence (a recent utility bill or lease). You can find your nearest office at ssa.gov or by calling 1-800-772-1213.

What happens after you enroll

Your Medicare card arrives in the mail within two weeks. It shows your Medicare number, which is different from your Social Security number. Keep this card with you when you see a doctor or go to the hospital.

If you enrolled in Part D or Medicare Advantage, your plan information arrives separately. Read the welcome packet — it lists which pharmacies and doctors are in your network, what your costs are, and how to file a claim if needed.

Your coverage starts on the first day of the month you turn 65 (or the first day of the following month if you enrolled after the 15th). Before that date, your current insurance is still your primary coverage. After that date, Medicare is primary.

Frequently Asked Questions

What if I miss my enrollment window?

You can still enroll during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage starts July 1. However, you will pay a permanent 10% surcharge on your Part B premium and a 1% surcharge on your Part D premium for every 12 months you delayed. The only exception is if you had employer coverage or may have access to for a Special Enrollment Period.

Do I have to enroll in Part D if I do not take any medications?

You do not have to enroll in Part D right now, but if you enroll in Original Medicare, you should enroll in Part D during your initial window even if you do not take medications. If you wait and then need prescriptions later, you will pay a 1% surcharge on your Part D premium for every month you delayed. If you choose Medicare Advantage, Part D is included automatically.

Can I change my mind after I enroll?

Yes. You have until December 31 of the year you turn 65 to make changes to your Part D plan or switch between Original Medicare and Medicare Advantage. After that, you can only change plans during the Annual Enrollment Period (October 15 through December 7 each year), and changes take effect January 1.

What if I am not a U.S. citizen?

You must be a U.S. citizen or a lawful permanent resident (green card holder) who has lived in the United States for at least five years to enroll in Medicare. When you enroll, you will need to provide proof of your immigration status. Bring your green card or other immigration documents to your Social Security office or have them ready if you enroll by phone.

Do I need to tell my current insurance that I am enrolling in Medicare?

You do not have to, but it is a good idea. Once Medicare becomes primary on your 65th birthday, your current insurance will coordinate with Medicare. Telling them in advance prevents confusion about which plan pays first. If you have employer coverage, your employer's benefits office can help coordinate the transition.