Losing Your Employer Health Plan After 65: Medicare Special Enrollment

Losing your employer health plan after 65 typically means it time to move over to Medicare and perhaps a Medigap plan. When you can enroll depends on if you have waived Medicare part B or not. Retirement, a layoff, or a company dropping its health plan can all trigger this process. Missing your Enrollment Period usually means a lifetime late enrollment penalty and a gap before your coverage restarts. Here’s how the window works, the mistake that trips up the most people, and what opens up once your Part B coverage begins.

When Does Your Special Enrollment Period Start if you Waived Part B?

If you or your spouse delayed Medicare Part B because you had group health coverage through current employment, you get an 8-month Special Enrollment Period once that coverage ends. The clock starts the month your employment stops or the month your group coverage ends, whichever happens first, not whenever you decide to formally apply. Source: Medicare.gov. Once Part A and Part B are both in place, most people also shop for a Medicare Supplement (Medigap) policy to help cover what Original Medicare doesn’t.

Does Your Former Employer’s Size Change Anything?

Yes. The 8-month Special Enrollment Period assumes your group health plan came from an employer with 20 or more employees, which is what makes it coverage Medicare treats as primary while you’re actively working. If your employer had fewer than 20 employees, Medicare typically became primary the day you turned 65, whether or not you kept working, so there may not be a delay to protect in the first place. Check with your HR department to confirm which side of that line applies to you. Our guide on working past 65 covers the small-employer rules in more detail.

What Happens If You Miss the 8-Month Window?

Missing the Special Enrollment Period means waiting for the General Enrollment Period, which runs January 1 through March 31 each year, and typically paying a penalty once your coverage starts. The Part B late enrollment penalty adds 10% to the standard premium ($202.90 in 2026) for every full 12-month period you went without qualifying coverage, and it’s generally charged for as long as you have Part B. Source: Medicare.gov.

💡 Tip: If you’re contributing to a Health Savings Account, signing up for Part A can create a tax problem, since Part A enrollment is backdated up to 6 months. That’s a tax question, not something our team advises on, so check with your HR department or a tax advisor first if you’re still funding an HSA.

How does COBRA affect Medicare Enrollment

This is where most of the trouble happens. Medicare only pauses your enrollment deadline for coverage based on current employment. COBRA is a continuation of a plan after the job has already ended, so it doesn’t count, and it doesn’t restart or extend your 8-month window even if you elect it the same week your job coverage ends. Someone who retires, takes 18 months of COBRA, and waits for it to run out before applying for Part B will find the window closed 10 months earlier than they assumed.

The safer move is to sign up for Part B when your employment or group coverage actually ends, regardless of what you decide to do with COBRA in the meantime. Our COBRA vs. Medicare at 65 guide walks through how the two can still work together once your timing is right.

How Enrolling in Part B Opens Your Medigap Window

The moment your Part B coverage takes effect, a separate 6-month Medigap Open Enrollment Period begins, as long as you’re 65 or older. Source: Medicare.gov. During those 6 months, an insurance company has to sell you any Medigap plan it offers in your state, can’t charge you more for pre-existing conditions, and can’t make you wait for coverage to start. For most people leaving a job at 65 or later, this is the cleanest path to a Medigap plan: no health questions, no denials, just a straightforward application.

This window is a one-time event, not something that resets every year like the Medicare Open Enrollment Period in the fall. It’s worth deciding ahead of time whether Med Sup or Medicare Advantage fits your situation better, since letting the 6 months pass unused generally means going through medical underwriting later. Our Medigap vs. Medicare Advantage comparison and Medigap overview cover the tradeoffs.

What If You Already Enrolled in Part B Before Losing Your Coverage?

Some people sign up for Part B at 65 even while still working, then lose their employer plan later. So since you already have Part A and B, the question becomes when you can enroll in Medigap or Medicare Part D.

If your Part B started more than 6 months ago: Your open enrollment window explained in the paragraph above has passed. You can still apply for a Medigap policy at any time of the year, but insurance companies are generally allowed to use medical underwriting—meaning they can review your health history to decide whether to accept your application or charge a higher price.

Some insurance providers will approve you if you can show proof of credible coverage through work within the last 63 days. If that isn’t the situation, a Medigap application will generally go through medical underwriting. Plenty of people with manageable conditions qualify. Our guide on retiring after your initial Medigap window walks through this scenario, and the Instant Medigap Underwriting Checker can show you what types of questions will be asked during underwriting.

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Getting Your Timing Right

Confirm the exact date your job or group coverage ends, apply for Part B to start when your work coverage ends. They enroll in a Medigap and part D drug plan to start on that same day. If you’d like help lining up the dates for your specific situation, get a Medigap quote at Senior65.com to see your options, or call 800-930-7956 to speak with our team. You’ll never pay more by working with us; carriers set the price and it’s identical everywhere.