Working Past 65

Working Past 65: Do I Need to Sign Up for Medicare?

By Tai Thao, Licensed Independent Medicare Agent, Golden Milestone Services · Updated September 15, 2026

If you are still working when you turn 65, you do not automatically need to leave your employer health plan and move entirely to Medicare. Some people can delay Part B without a late enrollment penalty, while others may need Medicare when they first become eligible. One of the most important questions is surprisingly simple: How many employees does the employer providing your health coverage have?

The 20-employee rule can change what you need to do at 65

If you are 65 or older and covered by a group health plan based on your current employment or your spouse's current employment, employer size helps determine which coverage pays first.

• 20 or more employees: The employer group health plan generally pays first and Medicare pays second. You may be able to delay Part B while that qualifying current-employment coverage continues.
• Fewer than 20 employees: Medicare generally pays first and the employer group health plan pays second. Medicare advises checking with the employer about enrolling in Part A and Part B when you first become eligible because the job-based plan might not pay properly if Medicare should be primary.

There can be additional rules for multi-employer plans, so do not make the decision based only on the number of people you see at your workplace. Ask the employer or benefits administrator how the plan coordinates with Medicare for an employee or spouse turning 65.

Should you take Medicare Part A while you are still working?

Most people qualify for Part A without paying a monthly premium. Medicare says that if you qualify for premium-free Part A, you can choose to enroll when you turn 65 or later. That is why many people who continue working consider taking Part A even if they delay Part B.

But there is an important exception: If you or your employer are contributing to a Health Savings Account, enrolling in Medicare can create a tax issue. Do not automatically enroll in Part A until you understand the HSA rule.

Have an HSA? Pay attention before enrolling in Part A

Once you have Medicare, you are no longer eligible to contribute to an HSA. The timing becomes especially important when you enroll in premium-free Part A after age 65 because Part A can begin retroactively for up to six months, but not earlier than the first month you were eligible for Medicare.

Medicare advises people with an HSA who delay Medicare to stop HSA contributions far enough in advance to account for this retroactive Part A coverage. If you plan to keep contributing to an HSA after 65, coordinate your Medicare enrollment date with your employer, tax professional or benefits administrator before applying.

Can you delay Part B without a penalty?

You may be able to delay Part B if you or your spouse are still working and you have qualifying group health coverage based on that current employment. Medicare allows eligible people to enroll in Part B while that coverage continues or during a Special Enrollment Period after the employment or coverage ends.

The key words are current employment. Your eight-month Special Enrollment Period generally begins when the employment ends or the job-based coverage ends, whichever happens first.

What if your spouse is the one still working?

You do not have to be the employee yourself. If you are covered by your spouse's employer group health plan based on your spouse's current employment, you may also be able to delay Part B and use a Special Enrollment Period later.

The same questions apply, just about your spouse's job. Is the coverage based on your spouse's current employment? How does that plan coordinate with Medicare? What happens to your coverage when your spouse retires or that coverage ends? Your Special Enrollment Period timing depends on when your spouse's employment or that coverage ends.

COBRA and retiree coverage are not the same as coverage from a current job

This is one of the easiest places to make a costly assumption. COBRA may let you keep the same employer plan for a limited time after you leave a job, but electing COBRA does not postpone your Medicare enrollment clock. Medicare says the Special Enrollment Period starts when you stop working or lose the job-based coverage, even if you choose COBRA.

Retiree coverage is also treated differently from coverage based on current employment. Keeping insurance that looks the same after you leave a job does not mean your Medicare enrollment rules stayed the same.

What makes the Part B late enrollment penalty permanent?

If you delay Part B without qualifying for a Special Enrollment Period, you may owe a late enrollment penalty when you eventually enroll. Medicare states that the Part B penalty is generally an additional 10% for each full 12-month period you could have had Part B but did not enroll, and in most cases you pay the penalty for as long as you have Part B.

That is why simply saying, "I have insurance through work," is not enough. You need to know whether the coverage is based on current employment and how that employer plan coordinates with Medicare.

Already over 65 and still working?

If you are already past 65 and delayed Part B because you kept employer coverage, that does not automatically mean you made a mistake. Many people can delay Part B while they are covered through qualifying current employment.

What matters now is confirming that your coverage actually qualifies, and planning your Part B enrollment before that employment or coverage ends rather than after.

What happens when you finally retire or lose employer coverage?

If you qualify for the employer group health plan Special Enrollment Period, you can generally enroll in Part B while you are still working and covered or for up to eight months after the employment or group health coverage ends, whichever happens first.

If you want Medicare to begin as your employer coverage ends, Medicare recommends enrolling in Part B before the job-based coverage ends rather than waiting until later in the eight-month window. This can help prevent a gap in health coverage.

What should you do three months before turning 65?

Three months before your 65th birthday is a good time to stop guessing and verify how your specific employer coverage works with Medicare.

• Ask your benefits administrator whether your coverage is based on current employment.
• Confirm whether the employer plan pays before or after Medicare once you turn 65.
• Ask whether you need Part A, Part B or both for the employer plan to continue paying correctly.
• Find out what happens to your own coverage when you retire or stop working.
• If you contribute to an HSA, review your Medicare timing before enrolling in Part A or applying for Social Security benefits.
• Compare the cost and coverage of staying on the employer plan with your Medicare options rather than assuming one is automatically better.
• If your spouse or dependents rely on your employer plan, find out what happens to their coverage if you make a change.

The right answer is not simply "everyone should enroll at 65" or "everyone who works can delay Medicare." Your employer size, type of coverage, HSA status and retirement timeline all matter.