You sign up for Medicare either automatically through Social Security or by actively enrolling during specific time windows. The exact steps depend on your age, work status, and whether you already get Social Security benefits.

Check if you get it automatically

If you already receive Social Security or Railroad Retirement benefits at least four months before you turn 65, you are usually enrolled automatically in Medicare Part A and Part B. In that case, a Medicare card is mailed to you before your coverage starts, and you only need to review it and decide if you want to keep Part B.

If you live in Puerto Rico or outside the U.S., you often get Part A automatically but may need to actively sign up for Part B. In that situation, contact Social Security or the Railroad Retirement Board to add Part B.

If you need to sign up yourself

If you are not yet taking Social Security when you turn 65, you usually must sign up for Medicare yourself. The main ways are:

• Apply online through the Social Security website by choosing the option to “Sign up for Medicare”.

• Call Social Security at 1‑800‑772‑1213 (TTY 1‑800‑325‑0778) or contact your local office to enroll.

• If you or your spouse worked for a railroad, contact the Railroad Retirement Board at 1‑877‑772‑5772.

Your Initial Enrollment Period is a 7‑month window: 3 months before your 65th birthday month, your birthday month, and 3 months after. If you miss it and do not qualify for a Special Enrollment Period, you may have to wait until the General Enrollment Period (January 1–March 31) and pay a late penalty.

Documents and information you’ll need

When you apply, you are usually asked for basic personal and work information. Helpful items include:

• Social Security number and proof of age (such as a birth certificate).

• Current address, phone, and email, matching your Social Security records.

• Work and health insurance details if you or a spouse are still employed and covered by an employer plan.

Having these ready makes the online application (often about 10 minutes) smoother. After approval, your Medicare card is normally mailed to you within a few weeks.

After signing up: next choices

Once enrolled in Original Medicare (Part A and Part B), you can decide whether to:

• Stay with Original Medicare and optionally add a stand‑alone Part D drug plan and/or a Medigap (supplement) policy.

• Enroll in a Medicare Advantage (Part C) plan that bundles Part A, Part B, and usually drug coverage, during your eligible enrollment periods.

These coverage choices have their own enrollment windows each year, such as the Annual Enrollment Period from October 15 to December 7. If you share your age, whether you already get Social Security, and if you’re still working with employer coverage, more tailored step‑by‑step guidance can be given.