When You Can Sign Up for Medicare Part A

Medicare Part A enrollment windows depend on your age and work history

You can sign up for Medicare Part A during specific periods set by Medicare, and the timing depends on whether you are turning 65, already receiving Social Security, or becoming disabled. Most people become may be able to access at 65, but some may have access to earlier due to disability or end-stage renal disease. Missing your enrollment window can result in a permanent penalty on your premiums, so understanding when your window opens matters.

The three main enrollment periods are the Initial Enrollment Period (the seven-month window around your 65th birthday), the General Enrollment Period (January 1 through March 31 each year), and Special Enrollment Periods (triggered by specific life events). Each has different rules about when coverage starts and whether penalties explore.

Key Takeaways

Your Initial Enrollment Period runs from three months before your 65th birthday through three months after, and this is when you should sign up to avoid penalties.
If you are already receiving Social Security benefits, Medicare Part A is usually automatic at 65 and requires no action on your part.
Signing up during the General Enrollment Period (January through March) means your coverage does not start until July of that year.
Late enrollment penalties on Part A premiums are permanent and equal 10 percent of the standard premium for each full year you delayed.
You can sign up through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

Your Initial Enrollment Period: the seven-month window around age 65

Your Initial Enrollment Period is the easiest time to sign up because coverage can start the month you turn 65 and there are no late penalties. This window opens three months before your birthday and closes three months after. For example, if you turn 65 in June, your enrollment period runs from March through September.

If you sign up during the first three months of this window (before your birthday), your coverage starts the month you turn 65. If you sign up in the month of your birthday or the three months after, your coverage starts the first day of the following month. This timing matters if you have other insurance or need coverage to begin on a specific date.

Automatic enrollment if you receive Social Security

If you are already collecting Social Security retirement, spousal, or survivor benefits before age 65, Medicare Part A is usually enrolled automatically three months before your 65th birthday. You do not need to do anything—Medicare sends you a card in the mail about two weeks before coverage starts on the first day of the month you turn 65.

Check the information on your Medicare card when it arrives. If something is wrong (such as a misspelled name or incorrect date of birth), contact Social Security at 1-800-772-1213 to correct it before your coverage begins. If you do not receive a card by the expected date, call 1-800-MEDICARE to confirm your enrollment.

The General Enrollment Period: January through March each year

If you miss your Initial Enrollment Period, you can sign up during the General Enrollment Period, which runs January 1 through March 31 every year. However, coverage does not start until July 1 of that year, creating a gap of several months between when you sign up and when protection begins.

You will also owe a late enrollment penalty on your Part A premiums. The penalty is 10 percent of the standard monthly premium for each full year you delayed signing up. This penalty is permanent—it stays on your bill for as long as you have Part A, even if you switch plans later. For this reason, the General Enrollment Period is a last resort, not a preferred option.

Special Enrollment Periods for specific life changes

A Special Enrollment Period allows you to sign up outside the normal windows if you experience certain events. These include losing employer health coverage, moving out of your plan's service area, or becoming a U.S. citizen or permanent resident. You typically have two months from the triggering event to sign up without penalty.

The rules for when coverage starts and whether penalties explore vary by the type of event. For example, if you lose employer coverage, you may be able to sign up and have coverage start when ready in the month you lose that insurance. Contact Medicare at 1-800-MEDICARE to report your life change and learn whether you may have access to for a Special Enrollment Period.

Early enrollment if you have a disability or end-stage renal disease

You may become may be able to access for Medicare before age 65 if you have been receiving Social Security Disability Insurance (SSDI) for 24 months, or if you have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS). Your enrollment rules are different from those for people turning 65.

If you receive SSDI, Medicare Part A starts automatically after you have been on disability for 24 months. You do not need to sign up. If you have ESRD or ALS, you can sign up during a special enrollment period tied to your diagnosis. Contact Social Security or Medicare to understand your specific timeline and whether any action is required on your part.

How to sign up for Medicare Part A

You have three main ways to sign up: online at Medicare.gov, by phone, or in person. The online method is fastest—go to Medicare.gov, create an account, and follow the prompts to enroll. You will need your Social Security number, date of birth, and citizenship information.

To sign up by phone, call 1-800-MEDICARE (1-800-633-4227). Representatives are available Monday through Friday, 8 a.m. to 8 p.m. Eastern time. You can also visit your local Social Security office in person with your Social Security card and proof of citizenship. Bring a photo ID and proof of residency (such as a utility bill or lease) to speed up the process.

What happens if you miss your enrollment window

Missing your Initial Enrollment Period does not disqualify you from Medicare, but it triggers consequences. You can still sign up during the General Enrollment Period (January through March), but your coverage will not start until July and you will owe a permanent late penalty.

The only way to avoid the penalty is to may have access to for a Special Enrollment Period based on a life event. If you think you have a valid reason for missing your window—such as not being informed about Medicare or being out of the country—contact Medicare at 1-800-MEDICARE to ask about penalty relief. Medicare can sometimes waive or reduce penalties in cases of exceptional circumstances, though this is not may provide.

Frequently Asked Questions

Do I have to sign up for Part A if I am still working at 65?

If you or your spouse are still working and have employer health coverage, you may be able to delay Part A without penalty under certain conditions. Contact Medicare or your employer's benefits office to confirm whether you may have access to for a Special Enrollment Period based on your work status. If you do not may have access to and miss your Initial Enrollment Period, penalties will explore.

What if I was not told about Medicare and missed my enrollment window?

Contact Medicare at 1-800-MEDICARE and explain your situation. Medicare can sometimes grant penalty relief if you can show you were not informed about your enrollment important date, though relief is not automatic. Have documentation ready, such as proof that you were out of the country or that you did not receive notices from Social Security.

Can I enroll in Part A without enrolling in Part B?

Yes. Part A and Part B have separate enrollment periods and rules. You can sign up for Part A alone during your Initial Enrollment Period without enrolling in Part B. However, if you delay Part B and sign up later, you may owe a late penalty on Part B premiums unless you may have access to for a Special Enrollment Period.

Does my spouse need to sign up at the same time I do?

No. Each person has their own enrollment period based on their own birthday or may be able to access date. Your spouse's Initial Enrollment Period is separate from yours. However, if your spouse is receiving Social Security based on your work record, they may be automatically enrolled when they turn 65.

What if I am not a U.S. citizen but live here legally?

You must be a U.S. citizen or permanent resident (green card holder) for at least five years to enroll in Medicare. If you meet these requirements, your enrollment period is the same as for citizens. If you do not yet meet the residency requirement, contact Medicare to learn when you will become may be able to access.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.