When Medicare Coverage Starts: Age, Disability, and Other Routes

Medicare starts at 65 for most people, but you can enroll earlier if you have a disability or end-stage renal disease

You become may be able to access for Medicare at age 65 if you are a U.S. citizen or permanent resident who has lived in the country for at least five years. You do not have to retire or stop working — age 65 is the threshold, regardless of your employment status. If you are already receiving Social Security benefits when you turn 65, Medicare enrollment happens automatically. If you are not yet taking Social Security, you need to sign up for Medicare yourself during your enrollment window.

You can also get Medicare before 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). These routes exist because certain conditions create medical costs that Medicare is designed to cover regardless of age.

Key Takeaways

Medicare enrollment at 65 is automatic if you are already on Social Security; otherwise you must sign up during your Initial Enrollment Period, which runs three months before and three months after your 65th birthday.
You can get Medicare before 65 if you have received SSDI for 24 months, have end-stage renal disease, or have ALS.
Missing your Initial Enrollment Period can result in a permanent penalty on your Part B and Part D premiums unless you have employer coverage or other may have access to circumstances.
Your coverage start date depends on when you enroll: enroll in the three months before your birthday and coverage starts the month you turn 65; enroll after and coverage starts the following month.

Automatic enrollment at 65 if you are on Social Security

If you are receiving Social Security retirement, survivor, or disability benefits when you turn 65, Medicare Part A and Part B are enrolled automatically about three months before your 65th birthday. You will receive a Medicare card in the mail. You do not need to do anything — the Social Security Administration handles the enrollment on your behalf.

Part A covers hospital stays, skilled nursing, hospice, and some home health care. Part B covers doctor visits, outpatient services, and medical equipment. Both are included in the automatic enrollment. You will also receive information about Part D (prescription drug coverage) and can choose a plan during the enrollment window if you want drug coverage.

Manual enrollment if you are not yet on Social Security

If you are not receiving Social Security when you turn 65, you must enroll in Medicare yourself. Your Initial Enrollment Period runs for seven months: three months before your 65th birthday, the month you turn 65, and three months after. You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

When you enroll matters for your start date. If you enroll during the three months before your birthday, coverage begins the month you turn 65. If you enroll in the month of your birthday or after, coverage starts the following month. For example, if your birthday is in June and you enroll in July, your coverage begins August 1.

Medicare before 65 through SSDI

You become may be able to access for Medicare after you have been on SSDI for 24 consecutive months. The 24-month clock starts the month your SSDI benefits begin, not the month you applied. Once you reach 24 months, you are automatically enrolled in Medicare Part A and Part B — no action required on your part. Social Security will send you a Medicare card.

This route exists because people with disabilities often face significant medical costs early in life. SSDI recipients do not have to wait until 65 to access Medicare's hospital and medical coverage. If you are unsure whether you have been on SSDI for 24 months, you can check your Social Security account online or call Social Security at 1-800-772-1213.

Medicare for end-stage renal disease and ALS

You can get Medicare when ready upon diagnosis of end-stage renal disease (ESRD) — kidney failure requiring dialysis or transplant — regardless of age. You do not have to wait any length of time. Medicare Part A covers dialysis, transplant surgery, and related services. You should report your ESRD diagnosis to Social Security as soon as possible so they can enroll you.

People with amyotrophic lateral sclerosis (ALS) also become may be able to access for Medicare right away, without the 24-month SSDI waiting period that applies to other disabilities. If you have been diagnosed with ALS, contact Social Security to begin the enrollment process. Both ESRD and ALS pathways recognize that these conditions create when ready and substantial medical needs.

What happens if you miss your enrollment window

If you do not enroll during your Initial Enrollment Period and you do not have may have access to coverage (such as employer health insurance), you will face a permanent penalty on your Part B premium. The penalty is 10 percent of the standard Part B premium for each full 12 months you were may be able to access but not enrolled. This penalty stays with you for life, even after you do enroll.

The same penalty applies to Part D (prescription drug coverage) if you go without creditable drug coverage for 63 days or more. A permanent late enrollment penalty on Part D is 1 percent of the national average premium for each month you were without coverage. These penalties are designed to encourage timely enrollment, and they do not go away if you change your mind later.

There are exceptions: if you had employer coverage or were covered under a spouse's employer plan, you may not face a penalty if you enroll within eight months of losing that coverage. If you believe you have a valid reason for missing your window, you can contact Social Security or Medicare to discuss your situation.

Enrollment timing and your coverage start date

The month you enroll determines when your coverage begins. Medicare uses a three-month window before your birthday to let people enroll early without delaying their start date. If you enroll in January and your birthday is in March, your coverage still starts in March. If you wait until April to enroll, coverage does not start until May.

This timing matters if you have upcoming medical needs or prescriptions. If you know you will need coverage by a certain date, enroll during the three months before that date. If you are unsure of your exact birthday or enrollment window, Medicare.gov has a tool to calculate your dates, or you can call 1-800-MEDICARE and speak with a representative who can walk you through the timeline.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65 if I am still working?

Yes. Working does not affect your may be able to access at 65. You can enroll and keep your job. If your employer offers health insurance, you may want to coordinate your Medicare enrollment with your employer coverage to avoid gaps or overlaps.

What if I am not a U.S. citizen but have a green card?

You can get Medicare at 65 if you are a permanent resident and have lived in the United States for at least five years. The five years do not have to be continuous, but they must add up to at least five years total. Bring your green card and proof of residency when you enroll.

Do I have to take Social Security at 65 to get Medicare?

No. You can enroll in Medicare at 65 without claiming Social Security retirement benefits. If you are not on Social Security, you must enroll in Medicare yourself during your Initial Enrollment Period. You can delay Social Security to a later age and still have Medicare coverage.

What if I turned 65 and did not enroll — can I still sign up?

Yes, but you may face a permanent penalty on your premiums if you do not have may have access to coverage. Contact Social Security or Medicare as soon as possible to enroll. Explain your situation; some people may have access to for exceptions, though they are limited. The sooner you enroll, the sooner your coverage begins.

How do I know if my SSDI has been running for 24 months?

Check your Social Security account at ssa.gov, or call Social Security at 1-800-772-1213. They can tell you the exact month your SSDI began and when you will reach 24 months. You do not need to do anything — enrollment happens automatically once you reach that mark.

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.