When and how to sign up for Medicare Part B

You sign up for Medicare Part B through Social Security, either online at ssa.gov, by phone at 1-800-772-1213, or in person at your local Social Security office. The timing matters: if you sign up during your Initial Enrollment Period — the seven-month window that starts three months before the month you turn 65 — you pay the standard monthly premium with no penalty. If you miss that window and do not have other health coverage, you will pay a higher premium for as long as you have Medicare.

Most people are automatically enrolled in Part B when they turn 65 if they are already receiving Social Security benefits. You can check your enrollment status on your Social Security account at ssa.gov or by calling Social Security directly. If you were automatically enrolled but do not want Part B, you must decline it in writing within a specific timeframe to avoid paying premiums you do not use.

Key Takeaways

  • You can sign up for Part B through Social Security online, by phone, or in person, and the best time is during the seven-month Initial Enrollment Period around your 65th birthday.
  • If you are still working and have health coverage through your employer, you may be able to delay Part B without a penalty — but you must tell Social Security about your coverage.
  • Missing your enrollment window without other coverage results in a permanent premium increase of 10 percent for each year you delayed.
  • You will need your Social Security number, proof of citizenship or legal residency, and information about any current health coverage when you sign up.
  • Part B covers doctor visits, outpatient care, and some preventive services, but you still pay a monthly premium, annual deductible, and 20 percent coinsurance for most services.

What documents you need to have ready

Before you contact Social Security, gather your Social Security number, proof of U.S. citizenship or legal residency (such as a birth certificate, passport, or naturalization papers), and your current health insurance information if you have it. If you are signing up in person, bring the originals or certified copies of these documents.

If you have coverage through a current or former employer, bring your insurance card and any paperwork that shows your employer's name and the dates your coverage is active. This information helps Social Security determine whether you may have access to for a Special Enrollment Period, which allows you to sign up for Part B later without the usual penalty.

The Initial Enrollment Period and what happens if you miss it

Your Initial Enrollment Period runs for seven months: it starts three months before the month you turn 65, includes the month you turn 65, and ends three months after. For example, if you turn 65 in June, your window opens in March and closes in September. During this time, you can sign up for Part B at the standard premium rate.

If you do not sign up during this window and you do not have other may have access to coverage, you will owe a late enrollment penalty. This penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but not enrolled. The penalty stays on your premium for as long as you have Medicare, so the cost of missing your enrollment period compounds over time.

Special Enrollment Period if you have employer coverage

If you are still working at 65 or have health coverage through a current or former employer, you may may have access to for a Special Enrollment Period that lets you delay Part B without a penalty. This applies only if your employer coverage is based on your current employment or your spouse's current employment. Coverage from COBRA, retiree plans, or the individual market does not count.

To use this exception, you must tell Social Security about your employer coverage before your Initial Enrollment Period ends. Then, when your employment ends or your employer coverage stops, you have eight months to sign up for Part B without a penalty. Keep documentation of your employer coverage — pay stubs, insurance cards, or letters from your employer — because Social Security may ask you to prove you had it.

The three ways to sign up

Online at ssa.gov: Create a my Social Security account if you do not have one, then look for the Medicare section. You can complete the sign-up process entirely online and receive confirmation by email. This is the fastest option if you have all your documents ready.

By phone: Call Social Security at 1-800-772-1213. Representatives are available Monday through Friday, 7 a.m. to 7 p.m. your local time. Have your documents nearby when you call. The wait time varies by time of day and season; calling early in the week or early in the morning usually means a shorter wait.

In person: Visit your local Social Security office. You can find the nearest one at ssa.gov/locator or by calling the main number above. Bring original or certified copies of your citizenship or residency documents. No appointment is required, but arriving early in the day usually means less waiting.

What Part B covers and what it costs

Part B covers doctor visits, outpatient hospital care, medical equipment, and some preventive services like cancer screenings and vaccines. It does not cover dental, vision, hearing aids, or long-term care. You pay for Part B through a monthly premium (the amount varies by income), an annual deductible, and 20 percent coinsurance on most services after you meet the deductible.

The standard Part B premium for 2024 is $164.90 per month, but higher-income beneficiaries pay more. If you receive Social Security benefits, the premium is deducted automatically from your check. If you do not receive Social Security, you will receive a bill each month. Many people pair Part B with a Medigap or Medicare Advantage plan to cover costs that Part B does not pay.

What happens after you sign up

After you sign up, Social Security will mail you a Medicare card within two weeks. Your coverage usually starts on the first day of the month after you sign up, though the exact date depends on when you submit your information. You can use your Medicare number to find doctors and hospitals that accept Medicare, and you can start using your benefits as soon as your coverage begins.

If you signed up online or by phone, you will receive a confirmation notice by mail. Keep this notice and your Medicare card in a safe place. You will need your Medicare number when you see a doctor, fill a prescription, or set up any other health coverage.

Frequently Asked Questions

What if I turn 65 while I am still working?

You can delay Part B without a penalty if your employer has 20 or more employees and you are covered under their health plan based on your current work. You must tell Social Security about this coverage before your Initial Enrollment Period ends. When you stop working or lose the coverage, you have eight months to sign up for Part B penalty-free.

Can I sign up for Part B after I turn 65?

Yes, but if you miss your Initial Enrollment Period and do not have may have access to coverage, you will pay a 10 percent penalty on your Part B premium for each year you delayed. You can sign up during the General Enrollment Period from January 1 to March 31 each year, with coverage starting July 1.

Do I have to take Part B if I do not want it?

If you are automatically enrolled, you can decline Part B in writing. Contact Social Security within the required timeframe (usually within the first three months of your enrollment) to request removal. If you decline and later change your mind, you may face a penalty unless you have a may have access to reason.

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

You can sign up for Part B if you are a lawful permanent resident (green card holder) and have lived in the United States for at least five years. Bring proof of legal residency when you sign up. Different rules may explore if you are a citizen of a country with a Medicare agreement with the United States.

How do I know if my doctor takes Medicare Part B?

Use the Medicare provider search tool at Medicare.gov, or call your doctor's office directly and ask if they accept Medicare. Most doctors do, but some may not, so it is worth checking before your first appointment.