If you aren’t receiving Social Security benefits yet, you’ll need to sign up for Medicare. For those born in 1943 or later, the Social Security full retirement age is 66 or older, so many people haven’t signed up for benefits by 65. This means they need to take steps to enroll in Medicare.

You can sign up for Medicare only at certain times. You can enroll in Medicare during your seven-month initial enrollment period, which starts on the first day of the month three months before the month you turn 65 and lasts for the entire three months afterward. Most people enroll in Parts A and B, but you may decide to sign up for just Part A.

You can delay enrolling in Part B if you or your spouse is still working and either of you has health insurance from an employer with 20 or more employees. Remember this job-based coverage from a current employer — not retiree health insurance or COBRA, which allows most people to stay on their company’s insurance plan for up to 18 months after they leave their job — allows you to defer signing up for Part B.
 

If you don’t want to sign up online using the instructions below, you may be able to apply at a local Social Security office. To avoid long lines, officials hope you’ll try to apply online. Otherwise, contact your local office to schedule an appointment or call Social Security at 800-772-1213.

1. To sign up, visit the Social Security Administration website. Click the sign up for Medicare button then click the Apply onlinebutton in the Sign up for Medicare box.

2. You’ll need to accept the terms of service. After doing so, click “Next.” On the Apply for Benefits page, choose “Start a New Application.” Note that you'll be asked to sign in to your online Social Security account or create one.
 

3. On the next screen, indicate whether you have an online Social Security account.
 

4. If you have an online Social Security account, you’ll need to log in.