You can sign up for Medicare Part A and Part B during your initial enrollment period, which starts three months before you turn 65

Your Initial Enrollment Period (IEP) runs for seven months: it begins three months before the month you turn 65, includes the month you turn 65, and ends three months after. During this window, you can sign up for Part A (hospital insurance) and Part B (medical insurance) without waiting or paying a penalty for late enrollment.

If you are already receiving Social Security benefits when you turn 65, Medicare Part A and Part B are usually started automatically. You will receive a Medicare card in the mail about two weeks before your 65th birthday. If you are not yet taking Social Security, you will need to sign up yourself. The process is straightforward and takes about 10 minutes online or over the phone.

Key Takeaways

  • Your Initial Enrollment Period is seven months long, starting three months before you turn 65, and this is when you should sign up if you are not automatically enrolled through Social Security.
  • You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
  • If you delay signing up after your Initial Enrollment Period ends, you may pay a permanent penalty on your Part B premium for each year you waited.
  • Part A covers hospital stays, skilled nursing care, and hospice; Part B covers doctor visits, outpatient care, and preventive services.
  • You will need your Social Security number, birth date, citizenship or immigration status, and information about current health coverage when you sign up.

Sign up online at Medicare.gov

The fastest way to sign up is through the official Medicare website. Go to Medicare.gov and look for the "Sign Up for Medicare" button on the homepage. You will be asked to create a login account using your email address and a password. This account lets you manage your Medicare information anytime.

Once you are logged in, you will answer questions about your personal information, including your Social Security number, date of birth, and citizenship status. The form also asks whether you currently have health insurance through an employer or union. Answer honestly — this information affects your coverage start date and any penalties. The entire process takes about 10 to 15 minutes, and you will receive a confirmation number at the end.

Call 1-800-MEDICARE to sign up by phone

If you prefer to speak with someone, call 1-800-MEDICARE (1-800-633-4227). Representatives are available Monday through Friday, 8 a.m. to 8 p.m. Eastern time, and Saturday, 8 a.m. to 4 p.m. Eastern time. Have your Social Security number, date of birth, and current insurance information ready when you call.

The representative will walk you through the same questions as the online form and will confirm your answers before submitting. They can also answer questions about what Part A and Part B cover, what your costs might be, and whether you need additional coverage. The call usually takes 15 to 20 minutes. You will receive a confirmation number and a follow-up letter in the mail.

Sign up in person at your local Social Security office

You can also visit your nearest Social Security office to sign up for Medicare. Find your local office at ssa.gov/locator or call 1-800-772-1213. Bring your Social Security card, birth certificate or passport, and proof of citizenship (such as a U.S. passport or naturalization certificate). If you are not a U.S. citizen, bring your green card or other immigration documents.

An employee will help you complete the enrollment form and answer your questions. This option works well if you prefer face-to-face help or if you have complex circumstances — for example, if you are still working and need to understand how your employer coverage affects your Medicare start date. Bring any current insurance cards so the employee can note them in your file.

What happens after you sign up

After you submit your enrollment, Medicare processes your information. You will receive a Medicare card in the mail within two to four weeks. The card shows your Medicare number, which you will use for all doctor visits and claims. Your coverage usually starts on the first day of the month in which you turn 65, or the first day of the following month if you sign up after your birthday month.

Before your coverage starts, you may want to choose a doctor who accepts Medicare and understand what your out-of-pocket costs will be. Part A has no monthly premium if you or your spouse paid Medicare taxes for at least 10 years. Part B has a monthly premium that varies by income; in 2024 it ranges from about $174 to $560 per month, depending on your income from two years ago. You will pay this premium directly to Medicare, usually through automatic deduction from your Social Security check or bank account.

What to do if you miss your Initial Enrollment Period

If you do not sign up during your seven-month Initial Enrollment Period, you can still sign up later, but you may face consequences. Part B has a late enrollment penalty — a permanent increase to your monthly premium of about 10 percent for each full 12-month period you delayed. For example, if you waited two years to sign up, your Part B premium would be about 20 percent higher than the standard rate, and you would pay this higher amount for as long as you have Part B.

Part A does not usually have a late enrollment penalty if you did not have employer coverage while you were working. However, if you had employer coverage and did not sign up for Part A within eight months of that coverage ending, you may face a penalty. If you missed your Initial Enrollment Period, you can sign up during the General Enrollment Period, which runs from January 1 to March 31 each year. Coverage would start July 1 of that year. You can sign up online, by phone, or in person using the same methods described above.

Special enrollment periods for people with employer coverage

If you or your spouse are still working and have health insurance through an employer or union, you may have a different enrollment window. You can delay signing up for Part B without penalty as long as you are covered by an active employer plan. When your employment or coverage ends, you have eight months to sign up for Part B without penalty — this is called a Special Enrollment Period.

To use this exception, you will need to show proof that you had employer coverage. Your employer's benefits office can provide a letter stating your coverage dates and that the plan was creditable (meaning it covered at least as much as Medicare Part B). Bring this letter when you sign up, whether online, by phone, or in person. This protection applies only to Part B; Part A enrollment rules are different and do not depend on employer coverage.

Frequently Asked Questions

Do I have to sign up for Part A and Part B at the same time?

You can sign up for them separately, but most people sign up for both during their Initial Enrollment Period. Part A is usually free if you paid Medicare taxes, so there is no reason to delay it. Part B has a monthly cost, so some people with employer coverage choose to delay Part B — but if you do, make sure you have a Special Enrollment Period that protects you from a late penalty.

What if I am still working at 65 and have employer insurance?

You can delay Part B without penalty as long as your employer plan is active and you are still employed. You do not need to sign up during your Initial Enrollment Period. When you leave your job or lose coverage, you will have eight months to sign up for Part B. Part A can usually be signed up for anytime without penalty, even if you are still working.

Can I change my mind after I sign up?

Yes. You have a limited time to change your coverage. If you sign up during your Initial Enrollment Period and change your mind, you can disenroll (cancel) your coverage during the same enrollment period or during the General Enrollment Period (January 1 to March 31). Contact Medicare at 1-800-MEDICARE to make changes.

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

You can sign up for Medicare if you are a lawful permanent resident (green card holder) who has lived in the United States for at least five years. You will need to bring your green card and proof of residency when you sign up. Refugees and asylees have different rules — call 1-800-MEDICARE to discuss your specific situation.

Will my Medicare card arrive before my coverage starts?

Not always. Your coverage usually starts on the first of the month you turn 65, but your card may arrive a few weeks later. You can use your confirmation number from enrollment to see your coverage details online at Medicare.gov before your card arrives. If you need to see a doctor before your card comes, bring your confirmation letter or show your confirmation number.