Key Takeaways

• Turning 65 is a major milestone, but Medicare eligibility doesn’t always automatically apply. Several exceptions and delays could affect when and how you qualify.

• Understanding the fine print behind work history, residency status, and enrollment windows can help you avoid costly mistakes or missed coverage.

Age Isn’t the Only Requirement

You may assume that reaching age 65 guarantees Medicare eligibility. But that’s only partially true. In 2025, Medicare eligibility is more nuanced. Yes, most individuals become eligible at 65, but it’s not a blanket rule. Several other factors play a key role, including:

• Your work history or your spouse’s

• Citizenship or legal residency status

• Whether you’re receiving Social Security benefits

• Whether you have end-stage renal disease or a disability

It’s essential to understand that age alone doesn’t unlock Medicare. Eligibility is tied closely to how long you’ve worked and paid into Medicare taxes (usually 10 years or 40 quarters).

Work History and Medicare Eligibility

To qualify for premium-free Medicare Part A at 65, you need at least 40 quarters (10 years) of Medicare-covered employment. If you don’t have this, you might still be eligible, but you’ll need to pay a monthly premium for Part A. In 2025, the standard premium for those with fewer than 30 quarters is $518/month, and $284/month for those with 30-39 quarters.

If you’re married, divorced, or widowed, your spouse’s work record may help you qualify. The key rule is that you must have been married for at least 10 years to use a former spouse’s record.

This work history requirement does not apply to Medicare Part B, but Part B requires a monthly premium. In 2025, the standard Part B premium is $185, and it must be paid whether or not you qualify for premium-free Part A.

What If You’re Still Working at 65?

If you’re still employed and have health insurance through your employer, you may not need to enroll in Medicare right away. However, this depends on the size of your employer:

• If your employer has 20 or more employees, your group plan usually remains the primary payer, and you can delay enrolling in Medicare without penalty.

• If your employer has fewer than 20 employees, Medicare becomes the primary payer. You may need to enroll to avoid gaps in coverage.

When you retire or lose employer coverage, you’ll get a Special Enrollment Period (SEP), lasting 8 months from the end of your job or group coverage—whichever comes first.

You Must Be a U.S. Citizen or Lawful Permanent Resident

To be eligible for Medicare at 65, you must be:

• A U.S. citizen, or

• A lawful permanent resident (green card holder) who has lived in the U.S. for at least 5 continuous years

Even if you meet the age and work requirements, your residency status can affect your eligibility. Temporary visas or short-term residence do not qualify.

Receiving Social Security? You’ll Be Automatically Enrolled

If you’re already receiving Social Security retirement benefits when you turn 65, you’ll be automatically enrolled in Medicare Parts A and B. Your Medicare card will arrive about 3 months before your 65th birthday.

But if you haven’t claimed Social Security yet, you need to actively sign up during your Initial Enrollment Period (IEP). This 7-month window includes:

• The 3 months before the month you turn 65

• The month of your 65th birthday

• The 3 months after your birthday month

Missing this window could result in late enrollment penalties for Part B and Part D.

Medicare Enrollment If You Delay Social Security

Many people choose to delay Social Security benefits to receive a higher monthly payout. If that’s your plan, just know it doesn’t delay Medicare eligibility.

You must manually enroll in Medicare during your IEP even if you haven’t yet claimed Social Security. Not doing so can lead to:

• A 10% Part B penalty for every 12-month period you delay without creditable coverage

• A late enrollment penalty for Part D unless you have other prescription drug coverage

Disability and Early Medicare Eligibility

Medicare isn’t only for those 65 and older. If you’ve received Social Security Disability Insurance (SSDI) for 24 months, you become eligible for Medicare automatically in the 25th month.

Some conditions may waive this waiting period. For example:

• Amyotrophic Lateral Sclerosis (ALS): Medicare starts immediately upon SSDI approval.

• End-Stage Renal Disease (ESRD): Medicare may start earlier, typically the 4th month of dialysis, or earlier if home dialysis or a kidney transplant is planned.

Not All Coverage Is Equal

Even once you’re eligible, you’ll still need to make choices. Medicare consists of multiple parts:

• Part A: Inpatient hospital care

• Part B: Outpatient medical care

• Part D: Prescription drug coverage

• Part C: Medicare Advantage (bundled plans from private insurers)

Parts A and B together are known as Original Medicare. You can also add Part D and a Medigap policy if you want to supplement coverage.

While most people assume Medicare covers everything, that’s not the case. You’ll still pay:

• Monthly premiums (especially for Part B and D)

• Annual deductibles

• Copayments and coinsurance

• Costs for services Medicare doesn’t cover (like dental, vision, or hearing aids)

Timing Is Critical to Avoid Gaps and Penalties

The most common enrollment pitfalls come down to timing. Missing your Initial Enrollment Period, or misunderstanding how employer coverage interacts with Medicare, can result in penalties or coverage delays.

If you miss your IEP and don’t qualify for a Special Enrollment Period, you can sign up during the General Enrollment Period (GEP), which runs from January 1 to March 31 each year. However:

• Coverage begins July 1

• Late enrollment penalties may apply

You May Still Need to Sign Up for Prescription Coverage

If you want prescription drug coverage, you must actively enroll in a Part D plan, unless you have other creditable coverage (like employer or union drug coverage).

The same 7-month IEP applies. Missing this deadline and not having other coverage may result in a permanent penalty—an added monthly cost for as long as you have Medicare.

Dual Eligibility: Medicare and Medicaid

If your income and assets are limited, you might qualify for both Medicare and Medicaid, a status known as dual eligibility. In this case:

• Medicaid may cover premiums, deductibles, and copayments

• You may qualify for a Special Needs Plan (SNP) tailored to dual-eligible individuals

Eligibility is determined at the state level. Even if you’re turning 65, your Medicaid eligibility depends on your current financial situation.

What to Watch for After You Enroll

Once enrolled, stay alert for important updates:

• Annual Notice of Change (ANOC): Sent each fall if you’re in a Medicare Advantage or Part D plan

• Open Enrollment: From October 15 to December 7 each year, allowing you to switch plans

• Income Reporting: Higher earners may pay more for Part B and Part D due to IRMAA (Income-Related Monthly Adjustment Amount)

Reviewing your coverage annually ensures you aren’t overpaying or missing critical benefits.

Your 65th Birthday Is Just the Starting Line

Becoming eligible for Medicare at 65 is not automatic for everyone. Whether it’s because of a lack of work credits, legal residency requirements, or employer coverage confusion, the assumption that eligibility is a given can lead to missed opportunities and higher costs.

Make sure you understand what boxes you need to check before your 65th birthday. Reach out to a licensed insurance agent listed on this website to get help reviewing your situation and making timely choices.