When You Become Eligible for Medicare: Age and Other Pathways

You become may be able to access for Medicare at age 65, but you can enroll starting three months before your birthday

Medicare may be able to access begins the first day of the month you turn 65. You do not have to wait until your birthday itself — you can sign up during the three months before you turn 65, and coverage will start on the first day of your birthday month. If you miss that window, you can still enroll, but your coverage will start later and you may pay a penalty for each month you delayed.

The three-month window before your 65th birthday is called your Initial Enrollment Period. It runs from three months before the month you turn 65 through three months after. This is the only time you can enroll without a penalty, so marking your calendar three months ahead is worth doing.

Some people become may be able to access for Medicare before age 65. If you have received Social Security Disability Insurance (SSDI) for 24 months, you may have access to for Medicare at any age. If you have End-Stage Renal Disease (ESRD) — permanent kidney failure — or ALS (amyotrophic lateral sclerosis), you may may have access to regardless of age. These are the only exceptions to the age 65 rule.

Key Takeaways

You become may be able to access for Medicare on the first day of the month you turn 65, and you can enroll up to three months before your birthday.
If you have received SSDI for 24 months, you become may be able to access for Medicare before age 65, even in your 50s or early 60s.
Missing your Initial Enrollment Period means your coverage starts later and you will pay a higher premium for Part B for as long as you have Medicare.
If you are still working at 65 and have health insurance through your employer, you may be able to delay enrollment without a penalty if your employer has 20 or more employees.

How SSDI leads to Medicare before 65

If you receive Social Security Disability Insurance, you automatically transition to Medicare after you have been on SSDI for 24 months. You do not need to explore again — Social Security will enroll you. The 24-month clock starts the month your disability benefits begin, not the month you applied.

This means some people in their 50s or early 60s will receive a Medicare card in the mail without having requested it. When this happens, you will receive a notice from Social Security explaining your coverage start date. If you are still working and have employer coverage, you can decline Medicare Part B (medical insurance) at that time, though you should keep Part A (hospital insurance).

Special cases: ESRD and ALS

If you have End-Stage Renal Disease and need dialysis or a kidney transplant, you become may be able to access for Medicare when ready, regardless of age. Your may be able to access starts the first month you begin dialysis or the month of your transplant, whichever comes first.

If you have been diagnosed with ALS, you become may be able to access for Medicare the first month you receive an ALS diagnosis and begin treatment. Unlike ESRD, there is no waiting period. You will need to contact Social Security to enroll, as they do not automatically sign you up the way they do for SSDI beneficiaries.

What happens if you miss your Initial Enrollment Period

If you turn 65 and do not enroll during your three-month window, you can still sign up later during the General Enrollment Period, which runs January 1 through March 31 each year. However, your coverage will not start until July 1 of that year, creating a gap in coverage.

More importantly, you will pay a late enrollment penalty on your Part B premium for as long as you have Medicare. The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but did not enroll. If you delayed for three years, you would pay 30 percent more than the standard premium. This penalty does not go away — it stays with you even after you finally enroll.

The same penalty applies to Part D (prescription drug coverage) if you go without it for more than 63 days after you become may be able to access. Part A (hospital insurance) does not carry a late enrollment penalty, but waiting to enroll means you have no hospital coverage during the gap.

Delaying enrollment if you have employer health insurance

If you are still working at 65 and your employer offers health insurance, you may be able to delay Medicare Part B enrollment without a penalty. This is called creditable coverage. The rule is that your employer must have 20 or more employees. If it does, you can stay on your employer plan and enroll in Medicare Part B later without penalty.

You must enroll in Medicare Part B within eight months after your employment ends or your employer coverage stops, whichever comes first. If you wait longer than eight months, you will owe the late enrollment penalty. You should contact Social Security or Medicare about three months before you plan to leave your job to understand your options and timing.

Part A (hospital insurance) is different. Even if you have employer coverage, you should enroll in Part A at 65 because it is free for most people and has no penalty for late enrollment. Delaying Part A can create gaps in coverage that are expensive to fill.

How to enroll during your Initial Enrollment Period

You can enroll in Medicare through three routes: online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. Online enrollment is usually the fastest — you can complete it in 15 to 20 minutes if you have your Social Security number and birth date ready.

If you are already receiving Social Security benefits, Medicare will contact you automatically about three months before you turn 65. You will receive a notice in the mail with your Medicare card and information about your coverage. You do not need to do anything if you want the standard coverage (Part A and Part B). If you want to make changes — such as choosing a Medicare Advantage plan instead of Original Medicare — you should act during your Initial Enrollment Period.

If you are not yet receiving Social Security benefits, you will need to contact Medicare or Social Security to enroll. Having your birth certificate, proof of citizenship or legal residency, and information about any current health insurance will speed up the process.

Understanding the different parts and when they start

Medicare has four parts, and they do not all start at the same time. Part A (hospital insurance) and Part B (medical insurance) are the foundation. If you enroll during your Initial Enrollment Period, both start on the first day of your birthday month. Part D (prescription drug coverage) also starts that month if you enroll during your Initial Enrollment Period.

Part C, also called Medicare Advantage, is an alternative to Original Medicare (Parts A and B). If you choose a Medicare Advantage plan, it replaces Parts A and B. These plans have their own enrollment rules and important date. The main enrollment period for Medicare Advantage runs October 15 through December 7 each year, though you can also enroll during your Initial Enrollment Period at 65.

If you enroll in Part D or Part C after your Initial Enrollment Period, your coverage will not start until the first day of the month after you enroll. This creates a coverage gap, which is why enrolling during your Initial Enrollment Period matters — your coverage starts when ready on the first day of your birthday month.

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 will begin on the first day of the month you turn 65. If you enroll after that three-month window closes, your coverage will start later and you may owe a late enrollment penalty.

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

If your employer has 20 or more employees, you can delay enrolling in Part B without penalty. You must enroll within eight months after you leave your job or your coverage ends. You should still enroll in Part A at 65 because it is free and has no penalty for delay.

Do I automatically get Medicare when I turn 65?

No. If you are already receiving Social Security benefits, Medicare will contact you and enroll you automatically. If you are not receiving Social Security, you must contact Medicare or Social Security to enroll. Missing your Initial Enrollment Period means you will have to wait until the next General Enrollment Period and will owe a late penalty.

What is the late enrollment penalty, and how long does it last?

The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but did not enroll. If you delayed three years, you pay 30 percent more. This penalty stays with you for the rest of your life, even after you finally enroll.

Can I get Medicare before 65 if I am disabled?

Yes. If you have received SSDI for 24 months, you become may be able to access for Medicare. If you have End-Stage Renal Disease or ALS, you may may have access to when ready regardless of age. Contact Social Security to confirm your may be able to access and enrollment.

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.