When and how to sign up for Part B coverage

You enroll in Medicare Part B during your Initial Enrollment Period, which runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after. If you miss this window, you can still enroll, but you may pay a permanent penalty on your monthly premium — roughly 10 percent more for each full year you delayed.

The actual enrollment happens through Social Security, Medicare.gov, or your local Social Security office. You do not need to visit an office; you can complete the process online or by phone. Social Security handles the paperwork and sends your Medicare card by mail within two to four weeks of approval.

If you are already receiving Social Security benefits when you turn 65, you are automatically enrolled in Part A and Part B unless you actively decline Part B. If you are not yet taking Social Security, you must enroll yourself during your Initial Enrollment Period or face delays and penalties.

Key Takeaways

  • Your Initial Enrollment Period is seven months long: three months before you turn 65, the month of your birthday, and three months after.
  • You enroll through Social Security online at ssa.gov, by phone at 1-800-772-1213, or in person at your local Social Security office.
  • If you delay enrollment past your Initial Enrollment Period, you will pay a permanent 10 percent monthly premium increase for each year you waited.
  • Part B covers doctor visits, outpatient care, and medical equipment; you pay a monthly premium and a yearly deductible before coverage begins.
  • You can change or drop Part B during the General Enrollment Period (January 1 to March 31 each year), though penalties still explore if you enroll late.

What Part B covers and what it costs

Medicare Part B is medical insurance that covers doctor visits, outpatient hospital care, diagnostic tests, mental health services, and durable medical equipment like wheelchairs and oxygen. It does not cover prescription drugs (that is Part D), dental, vision, or hearing aids.

The monthly premium for Part B varies by income. In 2024, the standard premium is $164.90 per month for most people, but higher earners pay more. The yearly deductible is $240, meaning you pay out of pocket until you reach that amount. After you meet the deductible, you typically pay 20 percent of the cost for most services; Medicare pays 80 percent.

Part B premiums are usually deducted automatically from your Social Security check. If you do not receive Social Security, Medicare bills you directly by mail.

Three ways to enroll: online, by phone, or in person

Online enrollment is the fastest route. Go to ssa.gov, create or log into your account, and select "Manage Your Benefits." You can complete the entire process in 10 to 15 minutes. You will need your Social Security number, date of birth, and contact information.

Phone enrollment takes about 20 minutes. Call Social Security at 1-800-772-1213 (TTY 1-800-325-0778 for deaf and hard of hearing). Have your Social Security number and Medicare card (if you already have one) ready. The representative will walk you through each question and confirm your enrollment before you hang up.

In-person enrollment at your local Social Security office is an option if you prefer to speak face-to-face. Bring your Social Security card, proof of citizenship or legal residency, and proof of age (birth certificate or passport). Wait times vary; call ahead to ask about current wait times at your office.

What happens if you miss your Initial Enrollment Period

If you do not enroll during your seven-month Initial Enrollment Period, you can still join Medicare Part B during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage begins July 1 of that year. However, you will pay a permanent monthly penalty for as long as you have Part B.

The penalty is 10 percent of the standard Part B premium for each full 12-month period you were may be able to access but not enrolled. If you waited two years, for example, you pay 20 percent more than the standard premium forever — even if you move to a different state or change plans later.

There are a few exceptions to the penalty. If you were covered by a group health plan through your job or your spouse's job when you turned 65, you may have a Special Enrollment Period that lets you join without penalty. You must enroll within eight months of losing that coverage or retiring, whichever comes first. Bring documentation from your employer showing the dates of your coverage.

Documents you will need to have ready

Gather these items before you start the enrollment process, whether online, by phone, or in person:

  • Your Social Security number
  • Your date of birth
  • Your current mailing address and phone number
  • Proof of U.S. citizenship or legal residency (birth certificate, passport, or naturalization papers) — required only for in-person enrollment
  • Your current Medicare card, if you already have one

If you are enrolling based on a group health plan exception, also have your employer's written confirmation of your coverage dates and the reason coverage ended (retirement, job loss, or plan termination).

After you enroll: what to expect next

Once you submit your enrollment, Social Security processes it within one to two weeks. You will receive a confirmation notice by mail that shows your enrollment date and your Part B premium amount. Your Medicare card will arrive separately within two to four weeks.

Your Part B coverage begins on the first day of the month after Social Security approves your enrollment. If you enroll in January, for example, coverage typically starts February 1. Your first premium payment is deducted from your Social Security check or billed by mail, depending on whether you receive Social Security benefits.

Once your card arrives, take it to your doctor's office and any hospital or clinic you plan to use. Providers need your Medicare number to bill Medicare for your visits. Keep your card in a safe place and bring it to every appointment.

Changing your mind: dropping Part B or switching plans

If you enroll in Part B and later decide you do not want it, you can drop it during the General Enrollment Period (January 1 to March 31). Your coverage ends on the last day of the month you request the change. However, if you drop Part B and later want to re-enroll, you will owe the late-enrollment penalty unless you have a may have access to reason.

If you want to keep Part B but change to a different Medicare plan (such as switching from Original Medicare to a Medicare Advantage plan), you can do so during the Annual Enrollment Period (October 15 to December 7 each year). Your new plan takes effect January 1. Part B itself does not change — only your supplemental or alternative coverage changes.

Frequently Asked Questions

Do I have to enroll in Part B if I am still working at 65?

If you or your spouse are still working and covered by a group health plan through that job, you can delay Part B enrollment without penalty. You have eight months after you or your spouse retires or the coverage ends to enroll. You will need written proof from your employer showing your coverage dates.

What if I turned 65 more than three months ago and did not enroll?

You can still enroll during the General Enrollment Period (January 1 to March 31). However, you will pay a permanent 10 percent monthly premium increase for each year you were may be able to access but not enrolled. The sooner you enroll, the sooner the penalty stops growing.

Can I enroll in Part B without Part A?

Yes, though it is uncommon. Most people are automatically enrolled in Part A at 65 because they or their spouse paid Medicare taxes while working. If you are not enrolled in Part A, you can enroll in Part B alone. However, you cannot enroll in Part D (prescription drug coverage) without Part A or Part B.

How long does it take to get my Medicare card after I enroll?

Social Security typically processes your enrollment within one to two weeks and mails your card within two to four weeks after that. In total, expect four to six weeks from the date you enroll. You can use your Social Security number as your temporary Medicare number at the doctor's office while you wait for your card to arrive.

What if I move to a different state after I enroll?

Your Part B coverage follows you to any state. Notify Social Security of your address change so your premium bills and Medicare correspondence reach you. You can update your address online at ssa.gov, by phone, or at your local Social Security office.