Working Past 65 and Medicare: What You Need to Know Before You Delay Enrollment

Turning 65 doesn’t automatically mean you have to retire.

Many people continue working past 65 — and that’s where Medicare timing can get confusing.

Should you enroll in Medicare at 65 if you’re still working?

If you’re still getting familiar with how Medicare is structured overall, start with our Medicare Basics guide before deciding what to delay.

Can you delay Part B?

Will you face penalties?

The answer depends on your specific situation.

Let’s walk through it clearly.

Do You Have to Enroll in Medicare at 65 If You’re Still Working?

Not always.

If you’re actively working and covered under an employer health plan, you may be able to delay certain parts of Medicare without penalty.

But the key factor is this:

How large is your employer?

Why Employer Size Matters

Medicare rules treat large and small employers differently.

If your employer has 20 or more employees:

• Your employer coverage is typically primary.
• Medicare is secondary.
• You may be able to delay enrolling in Part B without penalty.

If your employer has fewer than 20 employees:

• Medicare typically becomes primary at age 65.
• Your employer coverage may pay second.
• Delaying Part B could create gaps in coverage and potential penalties.

This is one of the most common areas of misunderstanding.

What About Medicare Part A?

Many people choose to enroll in Part A at 65 because it is often premium-free if you’ve worked and paid Medicare taxes for at least 10 years.

However, if you contribute to a Health Savings Account (HSA), enrolling in Part A can affect your ability to continue contributing.

This is another reason timing matters.

What Is Creditable Coverage?

If you delay Medicare, your employer coverage must be considered “creditable.”

Creditable coverage means it is expected to pay, on average, at least as much as Medicare would pay.

This matters especially for:

• Medicare Part B
• Medicare Part D

If your coverage is not creditable and you delay enrollment, you could face late enrollment penalties later.

What Happens When You Retire?

When your employment or employer coverage ends, you typically receive a Special Enrollment Period (SEP).

For Part B, this window generally lasts 8 months from the date employment or coverage ends.

This allows you to enroll without penalty — if your delay was valid.

It’s important not to assume you can wait indefinitely. These windows are time-sensitive.

You can review the full breakdown of Medicare enrollment periods and timing rules to understand how this window works.

Common Mistakes to Avoid

Some of the most common errors include:

• Assuming employer coverage automatically replaces Medicare
• Not confirming employer size
• Missing the Special Enrollment Period after retirement
• Delaying Part D without confirming creditable drug coverage

These mistakes are avoidable with a review before making changes.

Working Past 65 in Florida

For Florida residents — especially those working part-time, consulting, or covered under a spouse’s employer plan — Medicare coordination can vary.

Reviewing your situation before your 65th birthday (or before retirement) helps prevent unexpected gaps in coverage.

Retirement can also affect your Medicare premiums if your income changes. Learn how income impacts premiums in our guide to IRMAA and Medicare income adjustments.

The Bottom Line

You don’t automatically have to enroll in Medicare at 65 if you’re still working.

But you do need to understand:

• Employer size
• Creditable coverage
• Enrollment windows
• HSA implications

The right decision depends on your specific structure — not just your age.

Once you decide when to enroll, you’ll also need to compare your coverage options. Review the differences between Medicare Advantage and Medigap plans before making your final decision.