TRICARE and Medicare: How They Work Together
What Is TRICARE For Life?
TRICARE is the health care program for active-duty service members, military retirees, and their eligible family members. Once a TRICARE beneficiary becomes eligible for Medicare, usually at age 65, their coverage typically converts to TRICARE For Life (TFL).
TRICARE For Life is not a separate insurance plan you purchase. It is TRICARE’s way of wrapping around Medicare. To keep TRICARE For Life active, you generally must:
- Be entitled to Medicare Part A
- Enroll in and pay your Medicare Part B Premium
- Keep that Part B coverage active
If you let Part B lapse, you can lose your TRICARE For Life coverage. This is one of the most important facts for military retirees to understand, because it means TRICARE does not replace the need to enroll in Medicare. It works alongside it.
How TRICARE and Medicare Coordinate Benefits
When you have both Medicare and TRICARE For Life, the two programs coordinate so that, for most covered services, you have very little left to pay out of pocket. Here is the general order of operations:
- Medicare pays first for services covered by both Medicare and TRICARE.
- TRICARE For Life pays second, generally covering most or all of the remaining cost share for TRICARE-covered services.
- You typically owe little to nothing for services that both programs cover, as long as you see Medicare-participating providers.
For services that Medicare does not cover but TRICARE does (and vice versa), each program pays according to its own rules. This is part of why TRICARE For Life is often described as one of the most comprehensive coverage combinations available to retirees.
| Step | Who Pays | What Happens |
|---|---|---|
| 1 | Medicare | Pays its share first for Medicare-covered services |
| 2 | TRICARE For Life | Pays most or all remaining costs for TRICARE-covered services |
| 3 | You | Often owe little to nothing for in-network, covered care |
Why Most TRICARE Beneficiaries Should Not Buy a Medigap Plan
Medicare Supplement (Medigap) plans are designed to fill the gaps Original Medicare leaves behind, things like deductibles, copayments, and Coinsurance. That is exactly what TRICARE For Life already does for TRICARE-eligible beneficiaries.
For most people with TRICARE For Life, adding a Medigap plan means:
- Paying a monthly premium for coverage you likely do not need, since TRICARE For Life already covers most of what Medigap would cover
- Overlapping benefits that do not meaningfully reduce your out-of-pocket costs any further
- No added value in most situations, because TRICARE For Life’s coordination with Medicare already keeps your costs low
There can be unique individual situations where a licensed advisor might suggest reviewing your options, such as certain types of care that fall outside both programs’ coverage. But as a general rule, most TRICARE For Life beneficiaries find that a Medigap policy duplicates coverage they already have, at an additional cost.
If you are unsure whether your situation is an exception, it is worth a conversation with a licensed advisor before you commit to a monthly premium. You can learn more about how Medigap Guaranteed issue rights work in case your circumstances ever change.
Enrollment Mistakes to Avoid
Military retirees and their families sometimes run into trouble not because TRICARE and Medicare do not work well together, but because of enrollment timing. Here are the most common mistakes:
1. Delaying Medicare Part B enrollment
Some people assume that because they have TRICARE, they can skip or delay Medicare Part B without consequence. This is a costly misunderstanding. If you do not enroll in Part B when you first become eligible (and you do not have other qualifying coverage that allows you to delay), you risk:
- A late enrollment Penalty that can permanently increase your Part B premium
- A gap in TRICARE For Life coverage, since Part B enrollment is generally required to maintain it
Use the initial enrollment calculator to understand exactly when your enrollment window opens, and review when to sign up for Medicare benefits so you do not miss your window.
2. Letting Part B lapse after enrolling
Once you are enrolled, your Part B premium has to keep being paid. If it lapses, for example due to a billing issue or a missed payment, your TRICARE For Life coverage can be affected. Set up automatic payments or direct billing through Social Security to avoid this.
3. Not updating DEERS
The Defense Enrollment Eligibility Reporting System (DEERS) is the database that confirms your eligibility for TRICARE. If your information is out of date, especially your Medicare enrollment status, it can cause delays or denials in claims processing. Update DEERS as soon as your Medicare coverage becomes active.
4. Buying duplicate coverage out of uncertainty
It is understandable to want extra protection, especially when you are new to Medicare. But buying a Medigap plan or other supplemental coverage without first understanding how TRICARE For Life already works with Medicare can mean paying for benefits you will rarely, if ever, use.
A Quick Comparison: TRICARE For Life vs. Medigap
| Feature | TRICARE For Life | Medigap |
|---|---|---|
| Who it’s for | Military retirees and eligible family members with Medicare | Anyone enrolled in Original Medicare |
| Monthly premium | No separate TFL premium (Part B premium still applies) | Monthly premium varies by plan, carrier, and state |
| Fills Medicare gaps | Yes, generally covers most remaining costs | Yes, by design |
| Needed if you have the other | Rarely, in most situations | Not applicable if you already have TFL |
Frequently Asked Questions
Do I have to enroll in Medicare Part B if I have TRICARE?
In most cases, yes. To keep TRICARE For Life active once you are Medicare-eligible, you generally need to be enrolled in both Medicare Part A and Part B and keep paying your Part B premium.
Will I owe anything out of pocket if I have both Medicare and TRICARE For Life?
For most covered services from Medicare-participating providers, your out-of-pocket costs are typically very low because the two programs coordinate to cover most remaining costs after Medicare pays its share.
Should I buy a Medigap plan if I already have TRICARE For Life?
Generally, no. TRICARE For Life already fills most of the gaps that Medigap is designed to cover, so adding a Medigap plan usually means paying for overlapping coverage. A licensed advisor can confirm whether your specific situation is an exception.
What happens if I forget to enroll in Part B on time?
You could face a permanent late enrollment penalty on your Part B premium, and you risk a gap in your TRICARE For Life coverage. It is important to enroll during your initial enrollment window.
How do I make sure my TRICARE and Medicare information stays in sync?
Keep your DEERS record updated, especially after you enroll in Medicare, and confirm with TRICARE that your Medicare information is on file.
Bottom Line
TRICARE and Medicare are designed to work together, and for most military retirees and their families, TRICARE For Life already provides robust coverage once you are enrolled in Medicare Parts A and B. That is exactly why most TRICARE beneficiaries do not need, and should not buy, a separate Medigap plan.
The real risk is not the coordination between the two programs. It is missing your Medicare enrollment window or letting your Part B coverage lapse. If you want a second set of eyes on your situation, schedule a free Medicare consultation with REMEDIGAP. A licensed advisor can help confirm your enrollment timing and make sure nothing slips through the cracks.
This article is for educational purposes only and is not medical, legal, or financial advice. TRICARE and Medicare rules can change. Confirm your specific situation with TRICARE.mil, Medicare.gov, or a licensed advisor before making coverage decisions.
💡 Your next step: Once you have Medicare, most people add a supplement plan to cover out-of-pocket costs. Compare Medicare Supplement plans to find the right fit.
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Written by Michael Quinn
Licensed Broker, REMEDIGAP Founder
Fact Checked by Joann Quinn
Chief Compliance Officer
As a licensed insurance broker, REMEDIGAP upholds the principles of integrity in our editorial standards and ensures transparency in how we receive compensation from our insurance partners.