How does Medicare work with TRICARE?

Do I need Medicare Part A and Part B to keep TRICARE?

Yes, in most cases. TRICARE For Life (TFL) gives expanded medical coverage to Medicare-eligible uniformed services retirees 65 or older, to their eligible family members and survivors, and to certain former spouses, and you must have Medicare Part A and Part B to get TFL benefits. Medicare.gov tells people with TRICARE for retirees to sign up for both Part A and Part B when they're first eligible to keep their TRICARE coverage.

Your first chance to sign up is the 7-month Initial Enrollment Period, which starts 3 months before you turn 65 and ends 3 months after the month you turn 65. Active duty is the exception: if you're an active-duty service member or an active-duty family member, you don't have to sign up for Part B to keep your TRICARE coverage.

According to VA.gov, you don't enroll in TFL separately. After you enroll in Medicare Part A and Part B, TRICARE Prime automatically converts to TFL, and TFL starts once both parts are active. You can confirm your TFL eligibility in the Defense Enrollment Eligibility Reporting System (DEERS).

Who pays first, Medicare or TRICARE?

It depends on whether you're on active duty and where you get your care. Tell your doctors and other health care providers about all of your coverage so they send each bill to the right payer and avoid delays.

• Not on active duty: Medicare pays first for Medicare-covered services, and TRICARE may pay second.
• On active duty: TRICARE pays first for Medicare-covered services or items, and Medicare pays second.
• Military hospital or clinic, or any other federal health care provider: TRICARE pays. Medicare usually doesn't pay for services you get from a federal health care provider or other federal agency.

What does TRICARE For Life pay after Medicare?

According to VA.gov, TRICARE For Life covers deductibles, copays and costs for non-VA care that Medicare alone doesn't cover, and it also covers prescriptions and some other benefits. You can use any provider who accepts Medicare.

Medicare Part B has a monthly premium, $202.90 (standard) in 2026. VA health care and TFL also work together: enrolling in one doesn't cancel the other, and the VA doesn't bill Medicare or TFL for care you get at a VA facility. See how Medicare works with VA health care.

How does drug coverage work with TRICARE and Medicare Part D?

If you have TRICARE, you don't need to join a Medicare drug plan, and Medicare lists TRICARE as creditable prescription drug coverage (coverage expected to pay, on average, at least as much as Part D). 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, the Medicare drug plan pays first and TRICARE pays second.
• TRICARE and your Medicare drug plan may coordinate benefits if the plan's network pharmacy is also a TRICARE network pharmacy.
• The same is true for a Medicare Advantage Plan with drug coverage; otherwise, you can file your own claim to get paid back for your out-of-pocket costs.
• Because TRICARE is creditable coverage, a Special Enrollment Period lets you drop a Medicare drug plan or a Medicare Advantage Plan with drug coverage, or switch from a Medicare Advantage Plan with drug coverage to one without drug coverage, at any time.

What if I'm on active duty when I turn 65?

You have 8 months after the active duty service member retires to sign up for Part B through a Special Enrollment Period. Most people don't pay a premium for Part A, so Medicare.gov notes you might want to sign up for Part A when you turn 65, even if the active duty service member is still working, and wait on Part B because it has a monthly premium.

Before the active duty service member retires, you must sign up for both Part A and Part B to keep TRICARE without a break in coverage. Coverage starts the month after Social Security gets your completed forms, and you'll fill out an extra form showing you had TRICARE while the service member was on active duty.

What happens if I miss my Part B sign-up window?

If you don't sign up for Part B when you're first eligible, you might have to wait to sign up and go months without coverage, and you might pay a monthly Part B late enrollment penalty for as long as you have Part B: 10% for each full 12-month period you could have signed up but didn't. VA.gov adds that if you have TRICARE Prime, missing the deadline could also delay your automatic enrollment in TFL.

Medicare.gov also lists a Special Enrollment Period for people who have TRICARE that starts when Social Security notifies you and ends 12 months later; coverage begins the month after you sign up, or you may decide for coverage to begin after the end of your Initial Enrollment Period. If you missed a deadline, contact Social Security to ask about a general or special enrollment period. See What are the Medicare late enrollment penalties, and how do I avoid them?.