Part A is automatic for most people at 65, but you have to take the step to claim it

Part A is hospital insurance — it covers inpatient hospital stays, skilled nursing care after a hospital stay, hospice, and some home health services. If you are a U.S. citizen or permanent resident and you (or your spouse) paid Medicare taxes for at least 10 years, you get Part A automatically at age 65. You do not have to do anything to receive it. Your coverage starts the first day of the month you turn 65.

If you are not yet 65 and have been on Social Security Disability Insurance (SSDI) for 24 months, or if you have end-stage renal disease or ALS, you may get Part A earlier. The process is the same: it comes to you without a separate request.

The catch is that you still need to enroll formally to set up your coverage and receive your Medicare card. If you miss the enrollment window, you may face a penalty or a gap in coverage.

Key Takeaways

  • Part A coverage begins automatically on the first day of the month you turn 65 if you have paid Medicare taxes for at least 10 years.
  • You must enroll during your Initial Enrollment Period (the three months before, the month of, and the three months after your 65th birthday) to avoid penalties.
  • You can enroll through Social Security, Medicare.gov, or by calling Social Security directly — all three routes are free and take about 15 minutes.
  • If you miss your Initial Enrollment Period and do not have other health coverage, you will pay a 10 percent premium surcharge for as long as you have Part A.

When your enrollment window opens and closes

Your Initial Enrollment Period is seven months long: it starts three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your window runs from March through September.

You should enroll during this window even if you do not plan to use Medicare right away. If you have employer health coverage and you delay enrolling in Part A, you may still owe the surcharge later, depending on your employer's size and your coverage type. The rules are complex here — if you are still working or covered by an employer plan, contact Social Security before your birthday to confirm whether you can delay without penalty.

If you miss your Initial Enrollment Period, you can enroll during the General Enrollment Period (January 1 through March 31 each year), but you will pay a 10 percent higher premium for twice as long as you delayed — and the surcharge is permanent. This is one of the few Medicare penalties that never goes away.

How to enroll through Social Security

The easiest route for most people is to enroll when you claim Social Security benefits. If you are already receiving Social Security, Medicare.gov will enroll you automatically in Part A and Part B about three months before your 65th birthday. You will receive your Medicare card in the mail.

If you have not yet claimed Social Security, you can enroll in Medicare at the same time you file for Social Security. Visit your local Social Security office, call 1-800-772-1213, or go to ssa.gov. Tell them you want to enroll in Medicare. They will handle both applications together. Bring your birth certificate, proof of citizenship or permanent residency, and your Social Security number.

Processing takes about two to four weeks. You will receive your Medicare card by mail. If you need coverage to start on a specific date, enroll at least one month early.

How to enroll directly through Medicare

You can also enroll in Part A without going through Social Security. Visit Medicare.gov, click "Enroll in Medicare," and follow the online form. You will need your Social Security number, date of birth, and citizenship or residency status. The form takes about 10 minutes.

Alternatively, call Medicare at 1-800-MEDICARE (1-800-633-4227). A representative will walk you through the enrollment over the phone. This call is free and usually takes 15 to 20 minutes. Have your Social Security number and birth certificate information ready.

You can also visit your local Social Security office in person and ask to enroll in Medicare there, even if you are not claiming Social Security benefits yet.

What happens after you enroll

Once you enroll, Medicare processes your request and mails your Medicare card to the address on file. Standard delivery takes 7 to 14 business days. Your Part A coverage begins on the first day of the month you turn 65 (or the month you become may be able to access, if you may have access to before 65).

When your card arrives, check it for errors: your name, date of birth, and Medicare number should all be correct. If something is wrong, call Medicare at 1-800-MEDICARE to request a corrected card.

You do not need to do anything else. Part A is now active. You can use it at any hospital, skilled nursing facility, or hospice that accepts Medicare — which is nearly all of them.

If you are not yet 65 but may have access to early

If you have been on SSDI for 24 months, you become may be able to access for Part A automatically at the start of your 25th month on disability. You do not need to enroll — Medicare will contact you. You will receive your Medicare card in the mail about three months before your may be able to access date.

If you have end-stage renal disease (ESRD) or ALS (amyotrophic lateral sclerosis), you may get Part A when ready. Your doctor or dialysis center will help you file. The process is faster than the standard enrollment, but you still need to submit a formal request.

Common mistakes to avoid

The biggest mistake is missing your Initial Enrollment Period and not realizing it until later. The 10 percent surcharge is permanent — there is no way to remove it, even if you enroll years later. Mark your 65th birthday on your calendar now and enroll at least one month before it arrives.

Another common error is assuming you are automatically enrolled if you are already receiving Social Security. You are not — Medicare will enroll you, but you need to confirm you received your card. If you do not see it 30 days after your 65th birthday, call Medicare to check the status.

Do not assume you do not need Part A because you have private insurance. Even if you have employer coverage, you may still owe the surcharge if you do not enroll during your window. The rules depend on your employer's size and your coverage type — ask your HR department or call Social Security to be sure.

Frequently Asked Questions

Do I have to enroll in Part B at the same time as Part A?

No. Part A and Part B are separate. You can enroll in Part A alone and delay Part B if you are still working and covered by an employer plan. However, if you delay Part B beyond your Initial Enrollment Period without may have access to for an exception, you will pay a 10 percent surcharge for each year you were late. Talk to your employer's benefits team before you turn 65 to understand your options.

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

You must be a U.S. citizen or permanent resident (green card holder) to get Part A based on work history. If you are not, you may still get Part A if you have been a permanent resident for at least five years and meet other requirements. Call Social Security at 1-800-772-1213 to discuss your specific situation.

Can I enroll in Part A before I turn 65?

Yes. You can enroll up to three months before your 65th birthday. In fact, you should — it ensures your coverage starts on time and you receive your card before your birthday. If you wait until after you turn 65, there is a small risk of a gap in coverage if processing is delayed.

What if I already have Medicare from SSDI — do I need to do anything at 65?

No. Your Part A coverage continues automatically. Your Medicare number and card stay the same. You do not need to re-enroll or take any action. Your coverage straightforward transitions from disability-based to age-based at 65.

How much does Part A cost?

Most people pay no monthly premium for Part A because they paid Medicare taxes while working. However, you will pay a deductible when you use hospital services — the amount changes each year. In 2024, the Part A deductible is $1,632 per hospital stay. If you did not pay Medicare taxes for 10 years, you may have to pay a monthly premium; call Medicare to find out what you owe.