One of the most common — and most costly — mistakes Florida residents make as they approach Medicare eligibility is misunderstanding how Medicare and the ACA Marketplace interact. The short answer to "can you have both?" is: technically you can hold both cards, but doing so almost always results in wasted money, repaid tax credits, or dangerous coverage gaps.
This guide walks through the key rules governing Medicare and ACA Marketplace coverage in Florida, covering the most common transition scenarios, costly mistakes to avoid, and exactly what to do as you approach your 65th birthday or another Medicare eligibility trigger.
In This Guide
The ACA's Premium Tax Credit (APTC) is available to individuals who lack access to "minimum essential coverage" — and Medicare Part A qualifies as minimum essential coverage. The moment you are enrolled in Medicare Part A, you are ineligible for the APTC for any overlapping months.
This is not a gray area or a planning choice — it is a legal requirement. If you received advance APTC payments (monthly premium subsidies) during a period when you were also enrolled in Medicare Part A, you must repay those subsidies when you file your federal tax return.
| Coverage Situation | APTC Eligible? | What to Do |
|---|---|---|
| On ACA marketplace, not yet Medicare-eligible | Yes (if income qualifies) | Maintain marketplace plan normally |
| Enrolled in Medicare Part A (any reason) | No — APTC not allowed | Cancel marketplace plan immediately |
| Only enrolled in Medicare Part B (no Part A) | Yes — Part B alone does not disqualify | Unusual situation; consult a licensed agent |
| Enrolled in Medicare Advantage (Part C) | No — Part C includes Part A | Cancel marketplace plan immediately |
If you have been on a Florida ACA marketplace plan and are approaching your 65th birthday, here is the transition sequence you need to follow:
COBRA allows you to continue your employer's group health insurance for up to 18 months after leaving a job. It seems like a natural bridge to Medicare — but the interaction between COBRA and Medicare contains a trap that costs many Floridians thousands of dollars annually.
The core rule: Medicare is always primary over COBRA. This means:
If you are still working at 65 and covered by an employer group health plan, the rules depend on your employer's size:
| Employer Size | Primary Payer | Medicare Part B Strategy |
|---|---|---|
| 20 or more employees | Employer plan is primary; Medicare is secondary | You may delay Part B enrollment without penalty while actively employed; enroll within 8 months of losing employer coverage |
| Fewer than 20 employees | Medicare is primary; employer plan is secondary | Enroll in Medicare Part B on time — employer plan pays little to nothing if Medicare is primary and you lack Part B |
The "20 employee" rule is based on the employer's total workforce, not just your location or division. Verify your employer's size with your HR department — it determines the correct Medicare enrollment strategy and can prevent costly errors.
Health Savings Accounts (HSAs) are popular with Florida high-deductible plan enrollees for their triple tax advantage. But there is a critical rule that catches many people off guard: you cannot contribute to an HSA during any month that you are covered by Medicare Part A or Part B.
What makes this particularly tricky is Medicare's backdating rule. When you enroll in Medicare Part A after turning 65, your coverage can be backdated up to 6 months. This means HSA contributions made during those backdated months become unauthorized retroactively, triggering taxes and a 6% excise penalty.
Many Florida residents are enrolled in Medicare Part A without realizing it. If you began receiving Social Security retirement benefits before age 65, you were automatically enrolled in Medicare Part A on your 65th birthday. If you are already receiving Social Security and collecting marketplace subsidies, you may have been disqualified for APTC the moment your Medicare Part A started — even if no one told you.
Signs you may be in the inadvertent enrollment trap:
If you suspect you are in this situation, contact a licensed agent immediately. The sooner you address an overlapping enrollment, the smaller the potential APTC repayment obligation.
Florida Medicaid-eligible residents should not be on ACA marketplace plans at all — Medicaid is its own program and is not administered through the marketplace. If your income is below the Medicaid threshold in Florida (approximately 100% of the Federal Poverty Level for adults without children under Florida's limited expansion), you may be enrolled in Medicaid, not a marketplace plan.
If you qualify for both Medicare and Medicaid — called dual eligibility — you may qualify for a Dual Eligible Special Needs Plan (D-SNP), a type of Medicare Advantage plan that coordinates both programs. This is a far better option than maintaining a marketplace plan alongside Medicare.
For more on Medicare options across Florida, visit the Florida Plan Finder Medicare Guide. For ACA marketplace guidance, see Sun State Coverage and Get Florida Coverage.
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Can I have both Medicare and an ACA Marketplace plan in Florida?
Technically you can purchase both, but once you are enrolled in Medicare Part A, you are not eligible for the ACA Premium Tax Credit (APTC). Any subsidy you received for a marketplace plan during the same period as Medicare Part A coverage must be repaid when you file your federal taxes. In practice, enrolling in Medicare Part A terminates your eligibility for subsidized marketplace coverage and you should cancel your marketplace plan immediately to avoid repayment obligations.
What happens to my ACA plan when I turn 65 in Florida?
When you turn 65 and enroll in Medicare Part A (which is automatic if you are already receiving Social Security), your eligibility for ACA Premium Tax Credits ends the month your Medicare begins. Your marketplace plan does not automatically cancel — you must proactively contact healthcare.gov or your insurer to terminate coverage effective the date Medicare starts. Failure to do so results in APTC repayment for any month of overlap.
Is COBRA primary or secondary to Medicare?
If you have Medicare and then elect COBRA, Medicare is always primary and COBRA is secondary. You will be paying full COBRA premiums for coverage that only supplements what Medicare leaves behind. More dangerously, if you are on COBRA and turn 65, COBRA does not allow you to delay Medicare Part B enrollment without penalty — only active employer group coverage from a qualifying employer (20+ employees) qualifies for the Medicare Part B delay exception. Elect COBRA-as-bridge only with full understanding of these rules.
When do I have to stop contributing to my HSA if I am enrolling in Medicare?
You must stop HSA contributions at least 6 months before your Medicare Part A effective date. Medicare Part A can be backdated up to 6 months when you enroll after turning 65. Contributing to an HSA during a retroactively covered Medicare period triggers taxes plus a 6% excise penalty on the excess contributions. If you plan to enroll in Medicare at exactly 65, stop HSA contributions at age 64 and 6 months to be safe. Existing HSA funds can still be spent tax-free on qualified medical expenses after Medicare enrollment.
What is a Special Enrollment Period (SEP) for Medicare when leaving marketplace coverage?
Losing ACA marketplace coverage is generally not a trigger for a Medicare Special Enrollment Period. Medicare's SEP rules are based on age, disability status, and loss of qualifying employer group health coverage — not marketplace coverage. If you are past 65 and have been on an employer group plan that ends (because you retire or lose employment), you have an 8-month Special Enrollment Period to enroll in Medicare Part B without late enrollment penalties. Plan your transition accordingly — do not wait until your marketplace plan lapses to begin Medicare enrollment.