Who Can Enroll in Medicare and When

You become may be able to access for Medicare at age 65, regardless of your work history or income. If you are already receiving Social Security or Railroad Retirement Board benefits when you turn 65, Medicare enrollment happens automatically. If you are not yet collecting those benefits, you must sign up yourself during your enrollment window — usually the three months before the month you turn 65, the month itself, and three months after.

Some people under 65 can also enroll in Medicare. You may have access to if you have received Social Security Disability Insurance (SSDI) benefits for 24 consecutive months, or if you have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS). These are the only medical conditions that lower the age requirement.

If you miss your initial enrollment window, you can still sign up, but you may face a permanent penalty on your premiums. The penalty increases the longer you wait, so timing matters even if you cannot enroll right away.

Key Takeaways

  • You are may be able to access for Medicare the month you turn 65, and you should sign up during the seven-month window that starts three months before your birthday.
  • If you receive Social Security or Railroad Retirement benefits at 65, Medicare enrollment is automatic and you do not need to take action.
  • People under 65 who have received SSDI for 24 months, or who have ESRD or ALS, can enroll in Medicare regardless of age.
  • Missing your enrollment window results in a permanent increase to your Part B and Part D premiums, so sign up even if you plan to delay coverage.

Automatic Enrollment vs. Signing Up Yourself

If you are already collecting Social Security benefits three months before you turn 65, Medicare Part A and Part B enrollment happens without you doing anything. You will receive your Medicare card in the mail about two weeks before your 65th birthday. You do not need to call anyone or fill out forms.

If you are not yet receiving Social Security when you turn 65 — for example, because you are still working and chose to delay benefits — you must contact Social Security to sign up for Medicare. You can do this online at ssa.gov, by phone at 1-800-772-1213, or in person at your local Social Security office. Even though you are delaying Social Security, you can and should enroll in Medicare at 65 to avoid the late-enrollment penalty.

Railroad Retirement Board beneficiaries follow the same automatic rule as Social Security recipients. If you receive a Railroad Retirement annuity at 65, Medicare enrollment is automatic.

Enrollment Windows and What Happens If You Miss Them

Your Initial Enrollment Period (IEP) is a seven-month window: three months before the month you turn 65, the month of your birthday, and three months after. If you sign up during this window, your coverage typically starts on the first day of the month you turn 65 (or the first of the following month if you sign up after your birthday month).

If you miss your IEP, you enter the General Enrollment Period (GEP), which runs January 1 through March 31 each year. Coverage under GEP starts July 1 of that year. This delay means you go without coverage for several months, and you will owe premiums for the months you were not covered.

More importantly, missing your IEP triggers a late-enrollment penalty. For Part B, you pay an extra 10 percent of the standard premium for each full year you were may be able to access but not enrolled. For Part D (prescription drug coverage), the penalty is roughly 1 percent of the national average premium per month of delay. These penalties are permanent — they do not go away even after you finally enroll.

Special Circumstances That Change Your Enrollment Date

If you are still working at 65 and have health insurance through your employer, you may be able to delay Medicare Part B without penalty. This is called creditable coverage. You must have a group health plan based on your current employment (or your spouse's current employment), and the plan must cover at least 20 employees. If both conditions are true, you can wait to sign up for Part B until you or your spouse stops working or the coverage ends, whichever comes first. You then have eight months to enroll without penalty.

If you are a federal employee, you may have different rules. Contact your benefits office to confirm your enrollment window.

If you are not yet a U.S. citizen but are a permanent resident (green card holder), you can enroll in Medicare at 65 just as a citizen would. Citizenship is not required.

Enrolling Before Age 65 Due to Disability or Illness

If you have been receiving SSDI for 24 consecutive months, you become may be able to access for Medicare Part A (hospital insurance) automatically. You do not need to do anything — enrollment happens at the same time your SSDI benefits begin. Part B is optional and you can choose to enroll or decline.

If you have end-stage renal disease (ESRD), you can enroll in Medicare as soon as you begin dialysis or receive a kidney transplant, regardless of age. You will need to provide medical documentation of your condition. Contact Social Security or Medicare directly to start the process.

If you have ALS (Lou Gehrig's disease), you become may be able to access for Medicare when ready upon diagnosis, without waiting for SSDI benefits to begin. Again, you will need medical proof from your doctor.

How to Sign Up and What Documents You Need

To enroll in Medicare, you will need your Social Security number, proof of citizenship or permanent residency (such as a birth certificate, passport, or green card), and proof of age. If you are signing up by phone or online, you can usually provide this information verbally or upload documents. If you go to a Social Security office in person, bring originals or certified copies.

You can sign up through three routes: online at ssa.gov (fastest for most people), by phone at 1-800-772-1213 (Monday through Friday, 7 a.m. to 7 p.m. local time), or in person at your local Social Security office. Online enrollment typically takes 15 to 20 minutes. Phone and in-person appointments may take longer, especially during peak enrollment periods (October through December).

If you are under 65 and enrolling due to SSDI, ESRD, or ALS, contact Social Security or Medicare at 1-800-MEDICARE (1-800-633-4227) to confirm the process for your situation, as the steps differ slightly from standard age-65 enrollment.

What Happens After You Enroll

After you sign up, you will receive a Medicare card in the mail within two to four weeks. The card shows your Medicare number and which parts of Medicare you are enrolled in (Part A, Part B, Part D, or a combination). Keep this card with you and show it to doctors, hospitals, and pharmacies.

Your coverage begins on the first day of the month you turn 65 (or the first of the following month if you enroll after your birthday month). If you enrolled during the General Enrollment Period because you missed your Initial Enrollment Period, coverage starts July 1 of that year.

You will also receive a notice explaining your coverage and any premiums you owe. Part A (hospital insurance) has no monthly premium for most people. Part B (medical insurance) has a monthly premium that varies by income. Part D (prescription drug coverage) is optional and has a separate premium if you choose to enroll.

Frequently Asked Questions

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

You do not have to sign up for Part B if you have creditable coverage through your employer and meet the group size requirement (at least 20 employees). However, you should still sign up for Part A (hospital insurance) at 65 to avoid penalties. If you are unsure whether your coverage qualifies as creditable, ask your employer's benefits office.

What is the penalty for missing my enrollment window?

For Part B, you pay an extra 10 percent of the standard premium for each full year you were may be able to access but not enrolled. For Part D, the penalty is roughly 1 percent of the national average premium per month of delay. These penalties are permanent and explore every month you have coverage.

Can I enroll in Medicare before I turn 65?

Only if you have received SSDI for 24 months, have end-stage renal disease, or have ALS. Otherwise, you must wait until the month you turn 65. If you are close to 65, you can sign up during your Initial Enrollment Period, which starts three months before your birthday.

What if I am not a U.S. citizen?

You can enroll in Medicare at 65 if you are a permanent resident (green card holder) and have lived in the United States for at least five years. Citizenship is not required. Bring your green card and proof of residency when you sign up.

Will I receive my Medicare card automatically?

If you are already receiving Social Security benefits at 65, yes — your card arrives automatically. If you sign up yourself, you will receive your card in the mail within two to four weeks of enrollment. You can also view your Medicare information online through your Medicare.gov account before the physical card arrives.