Do I have to enroll in Medicare at age 65 if I am already collecting Social Security? 

Yes. If you are receiving benefits, the Social Security Administration will automatically sign you up at age 65 for parts A and B of Medicare. (Medicare is operated by the federal Centers for Medicare & Medicaid Services, but Social Security handles enrollment.) Social Security will send you sign-up instructions at the beginning of your initial enrollment period, three months before the month of your 65th birthday.

Medicare Part A covers basic hospital visits and some home health, hospice and skilled-nursing care. If you are receiving or are eligible to receive Social Security retirement benefits, you do not pay premiums for Part A.

Medicare Part B is akin to standard health insurance and carries a premium. The base rate in 2025 is $185 a month. Higher-income individuals pay more depending on the amount of income.

You can opt out of Part B — for example, if you already have what Medicare calls “primary coverage” through an employer, spouse or veterans’ benefits and you want to keep it. (Check with your current insurance provider to make sure your coverage meets the standard.) Opting out will not affect your Social Security status, but you might pay a penalty in the form of permanently higher premiums if you decide to enroll in Part B later. 

If you want to enroll in Medicare Part C (also known as Medicare Advantage), an alternative to Part B that is provided by private insurers, you must sign up on your own. The same goes for Medicare Part D, prescription drug coverage. You can find more information in Social Security’s “Medicare” publication and AARP’s Medicare Made Easy guide, or you can call Medicare at 800-633-4227.

Keep in mind

If you are living abroad or are outside the United States when you become eligible for Medicare, contact the nearest U.S. embassy or consulate to request an enrollment form.