You can start Medicare at 65, or earlier if you have a disability, end-stage renal disease, or ALS

Medicare may be able to access is tied to age for most people, but not everyone has to wait until 65. If you are 65 or older and a U.S. citizen or permanent resident, you can enroll. If you are younger than 65, you may still be able to start Medicare if you have been receiving Social Security disability benefits for 24 months, if you have end-stage renal disease (permanent kidney failure requiring dialysis or transplant), or if you have been diagnosed with ALS (amyotrophic lateral sclerosis, also called Lou Gehrig's disease). The month you turn 65 is the month your coverage can begin — you do not have to wait until your birthday itself.

Timing matters because there are penalties for signing up late. If you miss the window to enroll when you first become may be able to access, you will pay a higher monthly premium for as long as you have Medicare. The enrollment window is seven months long and centers on your birthday month, so understanding when that window opens and closes is the first step to avoiding extra costs.

Key Takeaways

  • You become may be able to access for Medicare the month you turn 65 if you are a U.S. citizen or permanent resident, or earlier if you receive Social Security disability benefits, have end-stage renal disease, or have ALS.
  • Your initial enrollment period is seven months long: three months before your birthday month, your birthday month itself, and three months after.
  • If you are still working and have health insurance through your job, you may be able to delay enrollment without penalty if your employer has 20 or more employees.
  • You must enroll during your initial period or pay a permanent penalty on your Part B and Part D premiums, even if you enroll years later.
  • Social Security will automatically enroll you in Parts A and B at 65 if you are already receiving benefits, but you must enroll in Part D yourself to avoid a late penalty.

The seven-month enrollment window around your 65th birthday

Your initial enrollment period runs for seven months: three months before the month you turn 65, the month you turn 65 itself, and three months after. For example, if you turn 65 in June, your window opens in March and closes in September. You can enroll online through Medicare.gov, by phone at 1-800-MEDICARE, by mail, or in person at your local Social Security office.

Coverage does not start the same month you enroll. If you enroll in March (three months before your birthday month), your coverage begins in May. If you enroll in your birthday month of June, coverage begins in July. If you enroll in July, August, or September (after your birthday month), coverage begins the month after you enroll. The only exception is if you enroll in the three months before your birthday month — then coverage can start as early as the month you turn 65.

This timing is important because it affects when you need to tell your current health insurance provider that you are leaving. If you have coverage through an employer or a private plan, you should notify them once you know your Medicare start date, so there is no gap or overlap in coverage.

If you are still working at 65

If you are still employed and your employer offers health insurance, you may not need to enroll in Medicare right away. If your employer has 20 or more employees, you can delay Medicare Part B enrollment without paying a penalty, as long as you are covered by your employer's plan and you are actively working. You must still enroll in Part A (hospital insurance) at 65, but Part B (medical insurance) can wait.

When you do leave your job or lose your employer coverage, you have eight months to enroll in Part B without penalty. This is called your special enrollment period. You will need to show proof that you had employer coverage — usually a letter from your employer's benefits department stating the dates you were covered and that the plan was group health insurance.

Part D (prescription drug coverage) works differently. If you lose employer drug coverage, you have 63 days to enroll in a Medicare drug plan without penalty. After that window closes, you pay a permanent penalty for every month you were not covered. If your employer's plan is considered "creditable coverage" (meaning it covers drugs as well as or better than Medicare does), you do not pay a penalty, but you should confirm this with your employer before you retire.

Enrolling before 65 if you have a disability or specific condition

If you are under 65 and have been receiving Social Security Disability Insurance (SSDI) for 24 months, you become may be able to access for Medicare automatically. You do not need to do anything — Medicare Part A and Part B will start the 25th month of your disability benefits. You should still enroll in Part D yourself during your initial enrollment period (which is still seven months, centered on your 65th birthday, even though you started Medicare earlier) to avoid a late penalty on drug coverage.

If you have end-stage renal disease, you can enroll in Medicare regardless of age. Your initial enrollment period is three months before the month your treatment begins, the month treatment begins, and 12 months after. If you are already receiving Social Security or Railroad Retirement benefits when your treatment starts, Medicare Part A will begin automatically, but you must enroll in Part B and Part D yourself.

If you have been diagnosed with ALS, you become may be able to access for Medicare when ready, without waiting for Social Security disability benefits to start. Your initial enrollment period is the month you are diagnosed, plus the following two months. Contact Social Security or Medicare directly to enroll, because this pathway is less commonly known and you may need to provide medical documentation of your diagnosis.

What happens if you miss your enrollment window

If you do not enroll in Part B during your initial enrollment period and you do not have a may have access to reason to delay (such as active employer coverage), you will pay a late enrollment penalty for as long as you have Medicare. The penalty is 10 percent of the standard Part B premium for each full 12-month period you were not enrolled. If you were supposed to enroll in 2024 but did not enroll until 2026, you would pay the penalty for two years — and that penalty stays on your premium permanently.

The same rule applies to Part D. If you go 63 days or more without creditable drug coverage, you pay a penalty of about 1 percent of the national average drug plan premium for each month you were not covered. This penalty also stays with you for life.

The only way to avoid these penalties is to enroll as soon as you realize you missed your window. There is no "second chance" enrollment period for most people, so if you think you may have missed your window, contact Medicare or Social Security when ready to confirm your status and enroll.

Automatic enrollment through Social Security

If you are already receiving Social Security retirement or disability benefits when you turn 65, Social Security will automatically enroll you in Medicare Parts A and B. You will receive a notice in the mail about three months before your 65th birthday. You do not need to do anything unless you want to decline Part B, which is rare and requires a written request.

However, Social Security does not automatically enroll you in Part D. You must enroll in a prescription drug plan yourself during your initial enrollment period, or you will pay a late penalty if you enroll later. You can enroll online at Medicare.gov, by phone, or through an insurance agent. The important date is the end of the third month after your birthday month — for example, if you turn 65 in June, you must enroll by September 30.

If you are not yet receiving Social Security when you turn 65, you must enroll in Medicare yourself. You can do this online, by phone, by mail, or in person at your local Social Security office. Having your Social Security number and proof of citizenship or permanent residency on hand will speed up the process.

Special situations: Delayed retirement, non-citizens, and government employees

If you delay claiming Social Security past your full retirement age, you can still enroll in Medicare at 65 without affecting your Social Security benefits. Your Medicare may be able to access and your Social Security claiming decision are separate. You can claim Medicare at 65 and delay Social Security to age 70 if you wish.

If you are a permanent resident (green card holder), you can enroll in Medicare at 65 the same way a citizen does. If you are not a permanent resident, you are not may be able to access for Medicare, even if you have lived and worked in the United States for many years. Undocumented immigrants and temporary visa holders cannot enroll.

If you worked for the federal government or certain state and local governments and are covered by a government pension instead of Social Security, you may still be may be able to access for Medicare at 65. However, your Medicare benefits may be reduced if you did not pay into Social Security for at least 30 years. Contact Social Security to find out how your government pension affects your may be able to access and your benefit amount.

Frequently Asked Questions

Can I enroll in Medicare before my 65th birthday?

Yes, your enrollment window opens three months before you turn 65. If you turn 65 in June, you can enroll starting in March. Coverage will not start until May at the earliest, but you can complete the enrollment process early to avoid missing the important date.

What if I turn 65 but am not yet receiving Social Security?

You must enroll in Medicare yourself during your seven-month initial enrollment period. Social Security will not automatically enroll you if you have not yet claimed benefits. You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

Do I have to enroll in all four parts of Medicare at the same time?

No. Part A (hospital) and Part B (medical) are usually enrolled together, but Part D (drugs) must be enrolled separately. If you delay Part B because you have employer coverage, you can still enroll in Part A. Enroll in Part D during your initial enrollment period to avoid a late penalty, even if you delay Part B.

What if I miss my enrollment important date by just a few days?

A few days over the important date still counts as late. There is no grace period. If you realize you have missed your window, contact Medicare or Social Security when ready to confirm whether you may have access to for a special enrollment period based on your specific situation.

Can I change my mind after I enroll in Medicare?

Yes, but only during certain times. You have a one-time chance to switch from Original Medicare to a Medicare Advantage plan (or vice versa) during the annual open enrollment period from October 15 to December 7. For other changes, you may may have access to for a special enrollment period if you have a may have access to life event, such as moving, losing employer coverage, or getting married.