TRICARE For Life & Medicare: How It Works and Who Pays First

TRICARE For Life is the version of TRICARE that military retirees move to at 65, and it works alongside Medicare rather than replacing it. You must have both Medicare Part A and Part B to get TFL benefits. Which program pays first then depends on your situation: off active duty, Medicare pays first and TRICARE may pay second; on active duty that order reverses; and at a military hospital or clinic, TRICARE pays and Medicare usually does not.

What TRICARE For Life is

TRICARE For Life (TFL) is the TRICARE coverage that works with Medicare. When you reach Medicare eligibility, which is generally at age 65, your TRICARE coverage transitions to TFL automatically as long as you meet its requirements. TFL is designed to coordinate with Medicare rather than stand in for it, and the order in which the two pay depends on where you get care and whether you are on active duty.1

This guide is specifically about TRICARE For Life. It is a separate program from Veterans Affairs (VA) health care, and the rules described here apply to TRICARE, not to VA coverage.

The defining feature of TFL is the requirement to carry Medicare alongside it. Once you are Medicare-eligible, you must have both Medicare Part A and Medicare Part B to get TFL benefits, so Medicare has to be in place for TFL to work at all.

TRICARE For Life is not only for the retiree. Medicare.gov describes TFL as providing expanded medical coverage to Medicare-eligible uniformed services retirees 65 or older, to their eligible family members and survivors, and to certain former spouses. Widows, widowers, and divorced former spouses of a retiree are easy to overlook here, and they belong on that list. The Part A and Part B requirement applies to each covered person individually: one person's Medicare enrollment does not cover another's.1

Why Part B is required to keep TRICARE

This is the rule that catches the most people off guard. To get TRICARE For Life benefits once you become Medicare-eligible, you must have Medicare Part A and Part B. Both are required, so without Part B in place you do not have TFL coverage. TRICARE states it plainly: when you use TRICARE For Life you pay no enrollment fees, but you must have Medicare Part A and Part B. You can confirm this on the TRICARE page on Medicare Part B premiums for TRICARE For Life.1

The reason is structural. For civilian care off active duty, TFL is built to sit behind Medicare, so it assumes Medicare is paying first. Without Part B in place, there is no primary coverage for the outpatient and physician services Part B covers. And Part B is a stated condition of TFL benefits in its own right, not just a practical convenience.

Because of this, timing your Medicare enrollment matters. For how Medicare enrollment windows work and how to avoid a gap, see Medicare enrollment periods. Enrolling in Part B when you are first eligible keeps your TRICARE coverage continuous.

How TRICARE For Life pays: three cases, not one

There is no single answer to who pays first. Medicare.gov's who pays first page splits TFL into three situations, and the one you are in changes the answer.1

If you are not on active duty. Medicare pays first for Medicare-covered services, and TRICARE may pay second. Read that word carefully, because medicare.gov bolds it: the page says TRICARE may pay second, not that it will. Treat TFL as coverage that is likely to follow Medicare rather than a guarantee that every cost Medicare leaves behind gets picked up.1

If you are on active duty and have Medicare. The order reverses. TRICARE pays first for Medicare-covered services or items, and Medicare pays second. This is the case that catches a Medicare-eligible family member of a sponsor who is still serving, and filing in the wrong order is how claims come back denied.1

If you get care at a military hospital or clinic, or any other federal health care provider. TRICARE pays. Medicare usually does not pay for services you get from a federal health care provider or other federal agency. This is the carve-out most likely to surprise you in practice, so do not plan around Medicare paying for care you get on base.1

What that means for your bill depends on which case you are in, and on whether TRICARE pays second at all. Because medicare.gov says only that TRICARE may pay second, do not assume every Medicare deductible and coinsurance amount is covered. For care neither program covers, the full cost falls to you. Ask the TFL claims contractor for your region what a specific service will cost before you count on it.1

What TRICARE For Life costs you

The main out-of-pocket cost of TRICARE For Life is not a TFL premium, because TFL itself has no enrollment fee or monthly premium. The cost is the Medicare Part B premium you must keep paying to stay covered. In 2026, the standard Medicare Part B premium is $202.90 a month, and higher-income beneficiaries pay more through an income-related surcharge. Part B is a condition of TFL benefits, so keeping Part B in force is what keeps TFL available to you.2,3,1

That surcharge is Medicare's income-related monthly adjustment amount, or IRMAA, and it is set from a tax return two years old. SSA's 2026 tables are headed "If MAGI in 2024 (or 2023 if 2024 is not available) was," so your 2026 Part B premium normally follows the modified adjusted gross income (MAGI) on your 2024 return, and falls back to your 2023 return when the 2024 one is not available.3

TFL is also not a standalone plan and does not replace Medicare. For services Medicare does not cover, standard TRICARE rules and cost-shares apply. For a service neither program covers, you pay out of pocket.

If you file your taxes separately from your spouse

Survivors and divorced former spouses hold TFL in their own right, and this is where their Part B bill can jump without warning. A married beneficiary who files a separate return and lived with their spouse at any time during the year goes on a compressed IRMAA scale rather than the single-filer brackets, and SSA treats that as its starting assumption rather than something you opt into. POMS tells staff that when the IRS reports a filing status of married filing separately, "assume the couple lived together at some point in the tax year." A beneficiary who lived apart from their spouse for the entire tax year has to allege that to SSA (POMS HI 01120.060) to be put on the single-filer brackets. Say nothing and you are billed on the compressed scale anyway: at $150,000 of MAGI that is $649.20 a month for Part B instead of $405.80, a gap of $243.40 a month, or about $2,921 a year.3

Those Part B amounts are not the final bill either. SSA footnotes its Part B column "Plus all applicable surcharges, minus Medicare Advantage Reduction," so a Part B late-enrollment penalty is added on top and a Medicare Advantage Part B reduction comes off. Because Part B is a condition of TFL benefits, this is not a cost you can decide to skip.3

There is also a protection you lose the moment any surcharge applies, and it catches retirees who have their Part B premium taken out of their Social Security payment. Federal Register notice 2025-20251 states that "The hold-harmless provision does not apply to beneficiaries who are required to pay an income-related monthly adjustment amount." Hold-harmless is what normally trims a Part B premium increase so it does not cut a Social Security recipient's net monthly payment. Cross into the first IRMAA tier by a dollar and you absorb the full increase instead, which means your net check can fall.3

If you are still working past 65

If you are still working at 65 and covered by an employer group health plan, Medicare's general rules let you delay Part B without a late penalty and use a Special Enrollment Period later, so long as that plan is a group health plan based on your own or your spouse's current employment. That is the Part B test, and it is worth getting straight: creditable coverage is the separate test that governs Part D, not Part B. The working-aged Special Enrollment Period runs at any time while that employment-based coverage continues, and for 8 months beginning the month the employment ends or the group health plan coverage ends, whichever comes first. But TRICARE For Life is built to sit on top of Medicare, so once TFL is your coverage you still need Part A and Part B in place to keep it. If you are weighing whether to delay Part B while you work, confirm the timing before you skip it, because a wrong call can leave you without TRICARE. See Medicare enrollment periods for how the Special Enrollment Period works.4,1

Prescription drugs: you do not need Part D

Medicare.gov is direct about this: if you have TRICARE, you do not need to join a Medicare drug plan. Your Part B enrollment protects the drug benefit too, because most people with TRICARE who are entitled to Part A must also have Part B to keep their TRICARE drug benefits. If you do join a Medicare drug plan anyway, your Medicare drug plan pays first and TRICARE pays second. That second payment is conditional rather than automatic: medicare.gov says TRICARE and your plan may coordinate their benefits if your plan's network pharmacy is also a TRICARE network pharmacy. So if you are shopping for a drug plan, check that overlap before you enroll instead of assuming TRICARE will pick up the rest at the counter.1

One thing to watch. The Part D late-enrollment penalty turns on creditable drug coverage: it applies if you go 63 or more continuous days after the end of your Part D initial enrollment period without either Part D coverage or other creditable drug coverage. CMS lists military-related coverage, including TRICARE, among the kinds of coverage that can count as creditable, so this is not a penalty most TFL beneficiaries are walking into. What decides it for your own plan is the sponsor's determination: every entity offering drug coverage has to decide each year whether what it offers is creditable and send Medicare-eligible members a disclosure notice saying so. Keep those notices, and confirm your status with TRICARE rather than assuming it. For how creditable coverage works, see Medicare creditable coverage. For Part D itself, see Medicare Part D.5

Do you need Medigap or Medicare Advantage?

The official coordination rules do not answer this, and it is worth knowing that before you act on advice that says they do. Medicare.gov's who pays first page sets out only the payment order described above, including that TRICARE may pay second when you are not on active duty. It does not say that holding TFL removes any reason to consider a Medigap policy or a Medicare Advantage plan. Anyone who tells you TFL makes those unnecessary is going beyond what that page states.1

If you are weighing one, talk to the TFL claims contractor for your region about how a specific plan would interact with your TFL benefits before you buy or drop anything. For background on what Medigap is and who it serves, see Medicare and Medigap. The requirement that does not change either way is keeping Medicare Part A and Part B.

TRICARE For Life and Medicare at a glance

Where to get help

Learn More

If you are a military retiree mapping out how Medicare and TRICARE For Life will fit together, you can find clear, step-by-step guidance at brevy.com.

The information on Brevy.com is for educational purposes only and is not a substitute for professional legal, financial, or medical advice. Rules vary by state and program and change frequently. Always verify with the relevant agency or a qualified professional. Brevy is not a law firm, financial advisor, or healthcare provider.