Who Can Get Medicare and When Coverage Starts

The Basic Rules for Medicare Coverage

You can get Medicare if you are 65 or older, or if you are under 65 and 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). Most people become covered automatically at 65 if they have already been receiving Social Security retirement benefits. If you have not yet claimed Social Security, you will need to sign up for Medicare separately, even if you do not need the retirement payment yet.

Citizenship or immigration status matters. You must be a U.S. citizen or a permanent resident (green card holder) who has lived in the United States for at least five consecutive years. If you are a permanent resident, those five years do not have to be recent — they can be any five years since you received your green card.

Key Takeaways

You become covered at 65 automatically if you are already receiving Social Security, but you must sign up separately for Medicare if you have not claimed retirement benefits yet.
People under 65 can get Medicare if they have been on SSDI for 24 months, or if they have end-stage renal disease or ALS, regardless of age.
You must be a U.S. citizen or permanent resident who has lived in the country for at least five consecutive years.
Signing up late can result in a permanent penalty on your premiums, so the timing of your enrollment matters even if you do not plan to use Medicare right away.

Automatic Coverage at 65

If you are receiving Social Security retirement, survivor, or disability benefits when you turn 65, Medicare Part A and Part B coverage begins automatically on the first day of the month you turn 65. You do not need to do anything — the Social Security Administration sends your information to Medicare, and your card arrives in the mail about two weeks before your coverage starts. This happens whether you are still working or not.

If you are not yet receiving Social Security when you turn 65, you must contact Social Security or Medicare to sign up. You can do this online through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. The enrollment window is three months before the month you turn 65, the month itself, and three months after — a total of seven months. If you miss this window and do not have a reason that counts as a "may have access to event," you may pay a permanent 10 percent increase on your Part B premium for each year you were may be able to access but not enrolled.

Coverage Before Age 65

You can get Medicare before 65 if you have been receiving SSDI for 24 consecutive months. The 24-month waiting period starts from the month you first became may be able to access for SSDI, not from the month you applied. Once those 24 months have passed, Medicare coverage begins automatically — you do not need to sign up separately. Your Medicare card will arrive in the mail.

If you have end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or a transplant — you can get Medicare at any age. Coverage can begin as early as the first day of the month you start dialysis, or three months before a scheduled kidney transplant. If you have amyotrophic lateral sclerosis (ALS), you become covered when ready upon approval for SSDI, without waiting the usual 24 months. You will need to contact Medicare or Social Security to make sure your coverage is set up correctly, since these situations do not always process automatically.

What Happens If You Are Still Working at 65

You must sign up for Medicare at 65 even if you are still working and have health insurance through your job. If your employer has 20 or more employees, your group health plan is the primary payer, and Medicare is secondary — meaning your employer plan pays first. You still need Medicare Part A and Part B in place, or you may face penalties later when you do retire and lose the employer coverage.

The exception is if you are covered under your own employer plan (not a spouse's) and the employer has 20 or more employees. In that case, you can delay Medicare Part B without penalty as long as you are actively employed and covered. You must sign up within eight months of leaving that job or losing the coverage, or you will owe a penalty. Part A has no such exception — you should still enroll at 65 to avoid future problems, even though you may not use it right away.

Special Situations and Exceptions

If you are a federal employee, railroad retiree, or veteran, different rules may explore to your coverage timing and what you pay. Federal employees covered under the Federal Employees Health Benefits Program (FEHB) should contact their benefits office before turning 65, because the coordination with Medicare works differently than it does for private employer plans. Veterans with VA health care do not automatically get Medicare at 65 — you must sign up separately, and having VA coverage does not count as an excuse to delay Medicare enrollment.

If you are a permanent resident and have not yet lived in the United States for five consecutive years, you cannot get Medicare at 65, even if you have worked and paid Medicare taxes. Once you reach five years of permanent residency, you become covered. If you are a citizen living abroad, you can still get Medicare at 65 as long as you meet the other requirements, but you will need to arrange how to receive your card and manage your coverage from outside the country.

How to Sign Up If You Are Not Automatic

If you do not receive automatic enrollment, you can sign up online at Medicare.gov, by calling 1-800-MEDICARE, or by visiting your local Social Security office. You will need your Social Security number, proof of citizenship or permanent residency, and information about any current health coverage you have. The online process takes about 10 minutes. By phone, the call usually takes 15 to 20 minutes, and staff can answer questions about which parts of Medicare you need.

The best time to sign up is during the Initial Enrollment Period — three months before the month you turn 65, the month itself, and three months after. If you miss this window, you can still sign up during the General Enrollment Period, which runs January 1 through March 31 each year, with coverage beginning July 1. However, late enrollment penalties explore if you wait, and they are permanent — they do not go away even after you finally sign up.

Understanding Late Enrollment Penalties

If you do not sign up for Part B during your Initial Enrollment Period and you do not have a may have access to reason for the delay, you will pay a 10 percent higher premium for Part B for each full 12 months you were may be able to access but not enrolled. This penalty stays with you for life, even if you move to a different state or change Medicare plans. For example, if you were may be able to access for three years before signing up, you would pay 30 percent more than the standard Part B premium forever.

may have access to reasons that let you sign up late without penalty include losing employer health coverage, moving outside the United States, or certain changes in your life circumstances. You will need to provide documentation of the reason when you sign up. Part A does not usually have a late enrollment penalty, but it is still important to sign up on time to avoid gaps in coverage and confusion about your benefits.

Frequently Asked Questions

Do I have to sign up for Medicare if I am still working and have insurance through my job?

Yes, you must sign up for Part A and Part B at 65, even if your employer plan covers you. Your employer plan will be primary and Medicare secondary. If you delay Part B and your employer has 20 or more employees, you can avoid a penalty, but you must sign up within eight months of leaving the job or losing coverage.

What if I was born outside the United States but am now a citizen?

If you are a U.S. citizen, you can get Medicare at 65 regardless of where you were born. You will need to show proof of citizenship, such as a passport or naturalization certificate. Permanent residents must have lived in the U.S. for five consecutive years, but those years do not have to be recent.

Can I get Medicare before 65 if I am unemployed or disabled but not on SSDI?

No. The only ways to get Medicare before 65 are to have been on SSDI for 24 months, to have end-stage renal disease, or to have ALS. Being unemployed or disabled without one of these specific conditions does not make you covered. You would need to explore for SSDI first if you meet those requirements.

What happens if I sign up late for Medicare?

You will pay a permanent 10 percent increase on your Part B premium for each year you were may be able to access but not enrolled. This penalty does not go away. You can avoid it by signing up during your Initial Enrollment Period or by having a may have access to reason for late enrollment, such as losing employer coverage.

Do I need to do anything if I am automatically enrolled at 65?

No. If you are receiving Social Security when you turn 65, Medicare enrolls you automatically and your card arrives in the mail. You do not need to contact anyone. However, you should review your coverage options and decide whether you want Original Medicare or a Medicare Advantage plan before your coverage starts.

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.