Guide

Still working at 65: job coverage and the Special Enrollment Period

Figures and rules on this page last checked against their sources: October 25, 2026.

Turning 65 while you or your spouse still work doesn't mean you must take Part B straight away. If a group health plan through current work covers you, you can usually wait and sign up later without a penalty. Whether that works for you depends on a few details.

First question: who pays first?

When you have both Medicare and a job-based plan, one pays first and the other pays second.

• The employer has 20 or more employees: the job plan pays first and Medicare pays second.
• Fewer than 20 employees: Medicare pays first and the job plan pays second.¹

The second case matters most. Medicare.gov warns that with a small employer, your job coverage might not pay for health services if you don't have both Part A and Part B, and says to check with the employer about signing up when you are first eligible.¹

So ask the benefits office two things directly: how many employees does the plan count, and how does it pay once you are 65?

Part A: often worth taking at 65

Most people pay no premium for Part A.² Medicare.gov notes that you may want to sign up for Part A at 65 even while you or your spouse are working, and wait on Part B because it has a monthly premium.³

One exception deserves a stop: health savings accounts. You can't put money into an HSA once you have Medicare. And when you sign up for Part A after 65, or apply for Social Security retirement benefits after 65, your Part A coverage starts up to six months back. Medicare.gov suggests you and your employer consider stopping HSA contributions at least six months before you apply, to avoid a tax penalty.⁴ Money already in the HSA can still pay Medicare costs.

The Special Enrollment Period

If you have group coverage through your own or your spouse's current job, you can sign up for Part B (and Part A, if you didn't take it) at any time while that coverage lasts. You also have 8 months after the job ends or the coverage ends, whichever happens first.³

Sign up within that time and no late penalty applies for the months you were covered through work. The penalty rules leave those months out of the count.⁵

The 8 months start on their own. Nobody sends a reminder when they begin.

One more condition is worth checking if you had a gap in coverage. The federal regulation for this Special Enrollment Period says you must have had the job coverage, or Part B, when you were first eligible at 65, and kept one or the other since.⁶ If you went without both at any point after 65, ask Social Security whether you still qualify before you count on it.

What doesn't count

Medicare.gov lists situations that do not give you this Special Enrollment Period:⁷

• COBRA. It isn't treated as coverage from current work, and taking it doesn't change when your 8 months end.
• Retiree coverage from a former employer, or the end of it.
• Marketplace coverage.
• Missing the 8-month window.

This is where people most often get caught. COBRA can look like the same plan, with the same card and the same doctors. For Medicare's purposes it isn't. If you leave a job at 66 and switch to COBRA, your 8 months still started when the job ended.

Retiree coverage has a further catch. Once you have Medicare because you are 65 or older, Medicare pays first and retiree coverage pays second. Retiree plans might not pay for costs during a period when you were eligible for Medicare but didn't sign up.¹

How to sign up when the job ends

If you want Medicare to start when your job coverage stops, Medicare.gov's advice is to sign up for Part B the month before you or your spouse retire. Coverage starts the month after Social Security gets your completed forms.³

If you sign up while still working, or within the first full month after job coverage ends, you can ask to delay your Part B start by up to three months.³

If you already have Part A, there are two forms:

• Form CMS-40B, the request to enroll in Part B.
• Form CMS-L564, the request for employment information. You fill in Section A. Your employer fills in Section B, which shows you had group coverage through current work.

You can also apply online through Social Security.⁸

Drug coverage and Medigap timing

If your job plan's drug coverage is creditable, meaning it is expected to pay at least as much as Medicare drug coverage, no Part D penalty builds up while you have it. Keep the notice of creditable coverage from your employer or union plan: it is the proof Medicare asks for if a penalty is ever questioned.⁹

When job coverage ends, you have 2 months to join a Medicare Advantage plan or a drug plan.¹⁰

Medigap timing is the subtle part. Your one-time six-month Medigap Open Enrollment Period starts when you sign up for Part B, even if you sign up while you still have job coverage.¹¹ So taking Part B early, without needing it, can use up those six months before you want a Medigap policy.

Spouses

Coverage through your spouse's current job counts the same way as your own.³ If your spouse is the one working and you are the one turning 65, the same questions apply: how big the employer is, who pays first, and when the 8 months would start.

A checklist for the year you turn 65

1. Find your Initial Enrollment Period with the window tool.
2. Ask the benefits office how many employees the plan counts and whether it pays first or second once you are 65.
3. Decide on Part A. If you have an HSA, settle the contribution question first.
4. If you wait on Part B, write down the date your job or coverage is expected to end, and the date 8 months after it.
5. Keep the employer's notice of creditable drug coverage.
6. The month before you retire, send Forms CMS-40B and CMS-L564, or apply online.

For free help with your own situation, contact your State Health Insurance Assistance Program.¹² If you missed a window already, see the Part B penalty and how to avoid it.