Who pays first: your job plan or Medicare?
When you have both Medicare and health coverage from a current job, one pays first (primary) and the other pays second. The size of the employer decides which:
| Your situation at 65 | Who pays first | Can you delay Part B without a penalty? |
|---|---|---|
| Coverage from your or your spouse's current job, employer has 20 or more employees | The job-based plan | Usually yes |
| Coverage from your or your spouse's current job, employer has fewer than 20 employees | Medicare | No: without Part B, the plan may pay very little |
| Under 65 with a disability, coverage from current work, employer has 100 or more employees | The job-based plan | Usually yes |
| COBRA, retiree coverage, Marketplace plan or VA care | Medicare (except VA care, which doesn't coordinate with Medicare) | No |
Multi-employer and union plans can follow special rules. Before you decide, ask your employer's benefits office in writing whether its plan pays first for people 65 and over, and whether it expects you to enroll in Part A or Part B. The job-coverage special enrollment period is for people with Medicare because of age or disability; if you have Medicare only because of kidney failure, the rules differ, so ask Social Security. See Medicare Part B.
Should I take Part A while I'm working?
If you qualify for premium-free Part A, many people take it at 65 even with job coverage; it can help pay hospital costs as secondary coverage. The exception is a health savings account (see below). If you'd have to pay a premium for Part A ($565 a month in 2026 with fewer than 30 quarters of work, or $311 with 30 to 39), you can usually delay it the same way as Part B while you have coverage from current work.
The Part B special enrollment period
When your or your spouse's job ends, or the job-based coverage ends, whichever comes first, you have 8 months to sign up for Part B without a late penalty. You can also sign up any time while you still have that coverage. If you sign up while you're still covered or during the first full month after the coverage ends, Part B can start the first day of the month you sign up or, if you ask, the first day of any of the next 3 months. If you sign up later in the 8 months, Part B starts the month after you sign up. Don't wait until the last month: if the 8 months pass, your next chance is the General Enrollment Period (January 1 to March 31), and the penalty adds 10% to your premium for each full 12 months without Part B, usually for as long as you have it.
- Get form CMS-L564 completed. Your employer fills out the Request for Employment Information to show the dates of your group coverage from current work. If the employer can't, Social Security accepts other proof, such as W-2s or pay stubs showing health premiums, or insurance cards with dates.
- Fill out form CMS-40B. This is the Application for Enrollment in Part B.
- Submit both to Social Security. Online at ssa.gov/medicare/sign-up, by fax or mail, or at a Social Security office. Keep copies. For help in Spanish, call 1-800-772-1213 and press 7.
- Join other coverage within 2 months. To join a Medicare Advantage or Part D plan, you have 2 full months after the month your job coverage ends.
Florida's Medigap windows when you retire
Retiring past 65 opens two chances to buy a Medigap policy without health questions in Florida:
- Your 6-month Medigap open enrollment starts the first month you're both 65 and in Part B. If you delayed Part B while working, it starts when your Part B does.
- Florida's 2-month group-coverage right: if you're in Part B, Florida law gives you 2 months after group health coverage ends to buy a Medigap policy without medical underwriting (s. 627.6741(1)(a)2, Florida Statutes). This helps people who took Part B while still working and then lose the job plan.
Florida has no birthday rule or yearly switching right, so outside these windows and federal guaranteed-issue rights, a company can ask health questions. See Medigap in Florida and enrollment periods.
Is my job's drug coverage creditable?
Part D has its own penalty. If you go 63 days or more in a row without Part D or other creditable drug coverage after your Initial Enrollment Period, you'll pay 1% of the national base beneficiary premium ($38.99 in 2026) for each full month without coverage, for as long as you have Part D. Drug coverage is creditable if it's expected to pay, on average, at least as much as standard Part D. Your employer or plan must send you a notice each year, usually before October 15, saying whether it is. Keep those notices: you may need them to prove you don't owe a penalty. When your job coverage ends, you have 2 full months to join a Part D plan. See Part D in Florida and the penalty calculator.
Health savings accounts (HSAs)
You can't contribute to an HSA once any part of Medicare has started, including premium-free Part A. You can keep using money already in the account for qualified expenses, including Medicare premiums (but not Medigap premiums).
If you sign up for premium-free Part A (or Social Security) after 65, Part A coverage can start up to 6 months before the month you apply, but not before the month you turned 65. Medicare.gov says to stop HSA contributions 6 months before you apply, to avoid a tax penalty on contributions made while you had Medicare. Talk with a tax professional about your own case.
If you want to keep contributing to an HSA, you can delay both Part A and Part B while you have coverage from current work at an employer with 20 or more employees. You can't delay Part A if you already get Social Security benefits, because Part A comes with them.
Covered through your spouse's job
The same rules apply when the coverage comes from your spouse's current work: if your spouse's employer has 20 or more employees, the plan pays first and you can usually delay Part B. When your spouse retires or the coverage ends, your 8-month window starts. If you're the one still working and your spouse turns 65 first, your spouse can usually stay on your plan as long as it pays first; check with your benefits office. If your spouse is younger than 65, losing your job coverage when you retire may leave them needing other coverage, such as COBRA or a Marketplace plan.
When you retire
- Sign up for Part B before your job coverage ends. Apply a month or two ahead so Part B starts the day after your job plan stops. Social Security accepts a Part B application during the 8-month window, but early is safer.
- Retiree coverage pays second. If your employer offers retiree health coverage, it usually requires Part A and Part B and pays after Medicare. Without Part B, you may pay most of the bill yourself.
- COBRA doesn't extend your deadline. Your 8 months start when employment or job-based coverage ends, even if you choose COBRA.
- Settle where you live. Many people retire to Florida or start splitting the year. Medicare Advantage and Part D plans are tied to your permanent residence; Original Medicare and Medigap work nationwide. See snowbirds and Medicare.
- Choose your coverage. Decide between Original Medicare with Medigap and Part D, or Medicare Advantage, and join within your windows. See plans for your ZIP code, or you can request a call from a licensed insurance agent to go over plans from the companies they work with.
Florida public employees
About 88.5% of Florida's state and local government employees were covered by Social Security on their jobs in 2023 (Congressional Research Service), so most earn premium-free Part A through their jobs, and the 20-employee rule decides who pays first while they work. About 11% weren't covered; if your public job didn't pay into Social Security, check your earnings record at ssa.gov/myaccount and ask Social Security how you qualify for Part A. Retiree coverage is where Florida's rules matter:
- Retiring from the State with State Group Insurance: once you're eligible for Medicare, the State plan pays after Medicare "even if you fail to enroll in Part B." Without Part B, you'd pay the share Medicare would have paid, about 80% of Part B-covered costs, so the State says it's in your financial interest to enroll. You can stay in a State PPO or HMO plan that pays secondary or join one of the State's group Medicare Advantage and prescription drug plans by sending your Medicare card to People First.
- Keep coverage at retirement: the State says that if you don't continue health insurance when you retire, or you cancel it later, you can't elect it again as a retiree. Call People First at 866-663-4735 (TTY 866-221-0268) before you retire.
- FRS Health Insurance Subsidy: Florida Retirement System retirees may qualify for a monthly payment based on years of service to help with health insurance costs. You don't have to be in the State plan to get it; you certify your coverage with the FRS.
- County, city and school district retirees: Florida law (s. 112.0801) lets retirees stay in their former employer's group plan, often paying the premium themselves. Ask the employer before you retire whether its plan requires Part B and how it works with Medicare.
See Florida state retirees and Medicare and State Group Insurance vs. individual Medicare plans.
Service members and federal employees
If you're on active duty at 65, TRICARE says you don't need Part B to keep TRICARE while on active duty. Sign up before you leave service, because TRICARE For Life requires Part A and Part B. See military, veterans and TRICARE in Florida. Federal employees still working are covered by the same 20-employee rule.
Sources
- Medicare.gov — Who pays first
- Medicare.gov — Which insurance pays first?
- Medicare.gov — When does Medicare coverage start?
- Medicare.gov — Avoid late enrollment penalties
- Social Security — Apply for Part B during a special enrollment period
- Social Security — Inscríbase en Medicare (Spanish)
- Florida Statutes — s. 627.6741, Medigap after group coverage ends
- Florida Division of State Group Insurance — Retiree FAQ (Part B, no re-enrollment)
- Florida Division of State Group Insurance — Retirees
- Florida Division of State Group Insurance — Medicare Advantage and Prescription Drug plans
- Florida Statutes — s. 112.363, FRS Health Insurance Subsidy
- Florida Statutes — s. 112.0801, local government retirees' group coverage
- Congressional Research Service — Social Security Coverage of State and Local Government Employees (R46961)
- TRICARE — TRICARE For Life
Frequently asked questions
Can I delay Medicare Part B if I'm on my spouse's employer plan?
Yes, if your spouse is still working and the coverage comes from that current job at an employer with 20 or more employees. When your spouse's job or the coverage ends, whichever is first, you have 8 months to sign up for Part B without a penalty. If your spouse has retired, the plan is retiree coverage and doesn't let you delay.
Do I need Medicare if I have COBRA?
Usually yes. COBRA isn't coverage from current work, so it doesn't extend your Part B deadline. Your 8-month special enrollment period starts when the job or job-based coverage ends, even if you take COBRA. If you already have Medicare when COBRA starts, COBRA usually pays second.
Can I keep contributing to my HSA after I sign up for Medicare?
No. Once any part of Medicare starts, you can't put new money into a health savings account, though you can still spend what's there. Because premium-free Part A can be backdated up to 6 months when you sign up after 65, Medicare.gov says to stop contributions 6 months before you apply for Medicare or Social Security.
What form do I need to sign up for Part B when I leave my employer plan?
Form CMS-40B, the Part B application, and form CMS-L564, which your employer fills out to show you had group coverage from current work. If your employer can't complete the L564, Social Security accepts other proof such as pay stubs showing health premiums or insurance cards. You can submit them online, by fax or mail, or at a Social Security office.
Can I buy Medigap without health questions when my job coverage ends in Florida?
Yes, if you're enrolled in Part B. Florida law gives you 2 months after group health coverage ends to buy a Medigap policy without medical underwriting. Separately, your federal 6-month Medigap open enrollment starts the first month you're 65 and in Part B, so delaying Part B also delays that window.
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