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Enrollment in Original Medicare

Some people are automatically enrolled in Original Medicare, while others have to enroll themselves. Enrollment in Original Medicare begins three months before your 65th birthday, during a time called the Initial Enrollment Period.

If you’re not currently working and are getting Social Security benefits, you will be automatically enrolled in Parts A and B on the first day of the month you turn 65, and you must pay a premium each month you have Part B. If you’re not working and are not receiving Social Security benefits, you will need to contact Social Security to enroll yourself.

If you’re still working at age 65 and have qualifying health coverage through your employer, you may choose to delay Part B. If you’re eligible for premium-free Medicare Part A, you don’t have to enroll in it, but you may still choose to do so because it can help cover costs not covered by your existing health plan. If you are contributing to a health savings account (HSA), you will not be able to continue doing so when you enroll in Part A.

Every enrollment situation is unique. Visit to learn about other enrollment scenarios and see if you should get Parts A and B External Site.

When you apply for Medicare, you have the opportunity to sign up for Part A and Part B at the same time. However, you can turn down Part B since you have to pay a premium for it, or because you may still have health coverage through an employer.

There are three ways to apply for Original Medicare (Parts A and B)

  • Online — Visit Social Security online External Site and follow the instructions. The application takes less than 10 minutes. After you submit the application, you will get a receipt and an application number you can use to check the status of your application later. Once you are enrolled, Social Security will send you a "Welcome to Medicare" packet that includes your Medicare card.
  • By Phone — Call the Social Security national customer hotline at 800-772-1213.
  • In Person — Visit your local Social Security office.

Be careful if you delay Part B enrollment

If you delay Part B enrollment and you do not have qualifying health insurance, the Centers for Medicare and Medicaid Services (CMS) will charge you a penalty once you do sign up. And, you will pay that penalty for as long as you have Part B coverage.

Medicare eligibility

You can enroll for Medicare as soon as you become eligible. You are eligible if:

  • You are 65 or older, a U.S. citizen and have been a legal resident for five straight years.
  • You are younger than 65, permanently disabled and have received Social Security disability payments for at least two years — or you need a kidney transplant or dialysis for end-stage renal disease (ESRD).

There are different times when you can enroll, depending on many factors. But, the first time you are eligible is during your Initial Enrollment Period.

If you’re still unsure, find out if you’re eligible External Site on and calculate your expected premium for Original Medicare. 

Initial Enrollment Period

When you are first eligible, you have seven months to sign up, during a time called the Initial Enrollment Period. It includes the three months before and after the month you turn 65, plus your birth month. For example, if your birthday is in March, your Initial Enrollment Period begins Dec. 1 and ends June 30.

Even though you can enroll at any time during this seven month period, your coverage will start no sooner than the month of your 65th birthday (or the month before if your birthday is on the first of the month.)

If you want to change Medicare supplement plans, you may do so any time of year. However, you may need to answer health questions if you are switching to a plan with more comprehensive benefits.

General Enrollment Period

If you miss your Initial Enrollment Period, you will have the chance to enroll in Medicare again during the General Enrollment Period, which takes place between Jan. 1 and Mar. 31 each year for a July 1 effective date. You may have to pay a late enrollment penalty if you miss your Initial Enrollment Period.

Plan for enrollment

The time your Medicare Part B coverage begins affects when you can sign up for Medicare supplement without needing to provide a health history. So, be sure to sign up for any supplemental coverage you need after you receive your Medicare card in the mail.

Medicare Supplement Plans opens new window