You can enroll in Medicare starting three months before you turn 65

Medicare enrollment opens on the first day of the month you turn 65, but you can sign up as early as three months before that birthday. The enrollment window stays open for three months after your birthday month — so if you turn 65 in June, you can enroll from March through August. If you miss this window, you may face a permanent penalty on your premiums, so the timing matters.

You do not have to wait until your 65th birthday to start coverage. You can choose any month within that seven-month window, and your coverage will begin on the first day of the month you pick. Most people enroll during the month they turn 65 so coverage starts when ready, but you have flexibility if your situation calls for it.

If you are already receiving Social Security when you turn 65, Medicare enrollment happens automatically — you do not need to do anything. If you are not yet taking Social Security, you will need to contact Medicare or Social Security to enroll.

Key Takeaways

  • You can enroll three months before your 65th birthday through three months after, with coverage starting on the first of any month you choose within that window.
  • If you are receiving Social Security at 65, Medicare enrollment is automatic; if not, you must contact Medicare or Social Security yourself.
  • Missing your initial enrollment window can result in a permanent 10 percent penalty on Part B premiums for each year you delayed, plus a similar penalty on Part D if you go without drug coverage.
  • You have different enrollment rules if you are still working and covered by employer health insurance, or if you live outside the United States.
  • Special enrollment periods allow you to sign up outside the normal window if you lose coverage, move, or experience certain life changes.

What happens if you miss the initial enrollment window

A late enrollment penalty applies to Part B (medical insurance) if you do not sign up during your initial seven-month window and you do not have other may have access to coverage. The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but not enrolled. That penalty stays on your premiums for as long as you have Medicare, so delaying by two years costs you 20 percent extra permanently.

Part D (prescription drug coverage) carries a similar penalty: 1 percent of the national average Part D premium for each month you went without coverage. If you go three years without Part D, you pay 3 percent extra on top of your premium for life. These penalties do not explore if you had other creditable drug coverage — employer insurance, TRICARE, or Veterans benefits count — during the time you were not enrolled in Medicare.

The only way to avoid these penalties is to have may have access to coverage from another source. If your employer offers health insurance and you are still working, you can delay Medicare without penalty as long as the employer coverage continues. Once you leave that job or lose the coverage, you have a special enrollment period to sign up without penalty.

Enrolling while you are still working

If you turn 65 while still employed and covered by your employer's health plan, you do not have to enroll in Medicare right away. You can delay Part B without penalty as long as the employer coverage is active and you are still working. However, you should still enroll in Part A (hospital insurance) at 65 even if you are working, because Part A is usually free and has no penalty for late enrollment.

When you leave your job or lose employer coverage, you have eight months to enroll in Part B without penalty. This is called a special enrollment period, and it is one of the few exceptions to the initial enrollment window rule. You will need to show proof that you had employer coverage — your employer or health plan can provide this documentation.

Part D rules are stricter: if you lose employer drug coverage, you have 63 days to enroll in a Medicare drug plan. After that window closes, the 1 percent monthly penalty applies for every month you were uninsured. Check with your employer about whether their plan is considered creditable coverage for drug benefits before you assume you can delay Part D.

Special enrollment periods outside the normal window

You can enroll in Medicare outside your initial seven-month window if you experience certain life changes. These special enrollment periods typically last 60 days and include situations like losing employer coverage, moving to a new state, getting married or divorced, or having a significant change in income. If you are a U.S. citizen living abroad, you also have different rules and can enroll during a special period.

To use a special enrollment period, you will need to provide documentation of the may have access to event — a termination letter from your employer, a lease showing you moved, a marriage certificate, or other proof depending on the circumstance. Contact Medicare directly to report the change and confirm you may have access to for the exception.

If you miss your initial window and do not have a may have access to special enrollment period, you can still enroll during the general enrollment period, which runs January 1 through March 31 each year. Coverage would begin July 1 of that year. However, late enrollment penalties will explore unless you had other may have access to coverage during the time you were not enrolled.

Turning 65 outside the United States

If you are a U.S. citizen or permanent resident living outside the country when you turn 65, you can still enroll in Medicare, but the rules are different. You have a special enrollment period that extends beyond the normal seven-month window — you can enroll anytime while you are outside the United States, plus four months after you return. This gives you more flexibility if you are living abroad.

Part A (hospital insurance) works the same way overseas as it does in the United States. Part B coverage is limited outside U.S. borders — Medicare generally does not cover care received outside the country except in very limited circumstances near the border. Many people living abroad choose to enroll in Part A only and purchase supplemental coverage from a private insurer that covers international care.

If you return to the United States, you have four months to enroll in Part B without penalty. After that window closes, standard late enrollment penalties explore. Contact Medicare before you move abroad to understand your options and confirm your enrollment status.

Coordinating Medicare with other coverage

If you have coverage from a current or former spouse's employer, TRICARE (military coverage), or Veterans benefits, your Medicare enrollment timing may be different. Some of these programs are considered primary to Medicare, meaning they pay first, and you can delay Medicare without penalty while that coverage is active. Other programs work alongside Medicare.

TRICARE for Life, for example, is secondary to Medicare, so you must enroll in both Part A and Part B at 65 to use TRICARE. If you are a veteran, VA benefits do not count as may have access to coverage, so you cannot delay Medicare based on having VA care. Retirees with military or federal employee health benefits should contact their plan administrator to understand how Medicare coordinates with their coverage.

If you are unsure whether your current coverage counts as may have access to coverage that lets you delay Medicare, contact your health plan directly. The plan administrator can tell you whether you can delay without penalty and what documentation you will need when you do enroll.

How to enroll and what you will need

You can enroll in Medicare through Social Security, Medicare.gov, or by calling 1-800-MEDICARE. If you are already receiving Social Security benefits, the enrollment happens automatically and you will receive your Medicare card in the mail about two weeks before your coverage starts. If you are not yet taking Social Security, you will need to contact one of these sources to enroll manually.

Have your Social Security number ready when you enroll. If you are enrolling in Part B or Part D, you will also choose a plan — there are many options, and the plans available in your area change each year. You can compare plans on Medicare.gov or call for help. If you do not choose a plan, Medicare will assign you one automatically, though it may not be the best fit for your needs.

Enrollment usually takes about 15 minutes by phone or online. Your coverage will begin on the first of the month you choose, and you will receive your Medicare card in the mail. Keep your card with you when you see a doctor or fill a prescription.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65?

Yes. You can enroll starting three months before your 65th birthday. Your coverage can begin on the first of any month within your seven-month enrollment window — three months before through three months after your birthday month. Most people choose the month they turn 65 so coverage starts right away.

What if I am still working at 65 and have health insurance through my job?

You can delay Part B without penalty as long as you are working and covered by your employer's plan. You should still enroll in Part A at 65 because it is usually free. When you leave your job, you have eight months to enroll in Part B without penalty. Part D rules are stricter — you have only 63 days after losing employer drug coverage.

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

No. You can enroll in Part A and Part B separately, and you can choose Part D at a different time. However, delaying Part B or Part D outside your initial enrollment window will trigger late enrollment penalties unless you had other may have access to coverage. Part A has no late enrollment penalty.

What is a special enrollment period and when do I get one?

A special enrollment period lets you enroll outside your initial seven-month window if you lose employer coverage, move, get married or divorced, or experience other may have access to life changes. These periods usually last 60 days. You will need to provide proof of the may have access to event, such as a termination letter or marriage certificate.

What happens if I miss my enrollment window and do not have other coverage?

You can still enroll during the general enrollment period (January 1 through March 31), with coverage starting July 1. However, late enrollment penalties will explore permanently to Part B and Part D unless you had other may have access to coverage during the time you were not enrolled in Medicare.