TRICARE For Life at 65: You Must Take Medicare Part B to Keep TRICARE, What It Costs in 2026, and the Sign-Up Window TRICARE Sets

TRICARE For Life starts on the first day you have both Medicare Part A and Part B, with no enrollment form and no TRICARE enrollment fee. That is the whole mechanism, and it cuts both ways: at 65, if you are eligible for premium-free Part A, you must also have Part B to keep any TRICARE coverage beyond prescriptions filled at a military pharmacy. The rule sits in 10 U.S.C. 1086(d), TRICARE's newsroom notice of October 15, 2026 repeats it, and the Defense Health Agency's August 2026 brochure says when to sign up. Settled for 2026: the standard Part B premium is $202.90 a month, the Part B deductible is $283, and TRICARE's catastrophic cap under TFL is $3,000 per family. Not settled: the 2027 Part B premium, which CMS has not announced. The 2026 figure came out on November 14, 2025.

The rule, and where it comes from

The statute first. 10 U.S.C. 1086(d)(1) says a person entitled to Medicare Part A "is not eligible for health benefits under this section," the section that covers retirees, their family members and survivors, and paragraph (d)(2) lifts that bar only for a person who "is enrolled in" Part B. There is no age in the sentence. It bites at 65 because that is when most people become entitled to premium-free Part A. TRICARE's October 15 notice puts it in plain words: "At age 65, if you're eligible for Medicare Part A, you must have both Medicare Part A and Medicare Part B to keep your TRICARE coverage."

Once both parts are in effect, nothing else happens on your side. TFL "has no enrollment forms or enrollment fees." Medicare pays first and forwards the claim to the TFL contractor, and TRICARE pays what is left for care both programs cover. If you also carry other health insurance, TRICARE pays last. Medicare does not require a referral to see a specialist. Eligibility is individual: when you turn 65 and move to TFL, a spouse under 65 stays on TRICARE Prime or Select until their own 65th birthday.

• Active duty families do not need Part B yet. A family member who turns 65 while the sponsor is still serving keeps Prime or Select without Part B. The brochure's rule: sign up "no later than the month their sponsor's active duty status ends," using a Special Enrollment Period that is open any time the sponsor is on active duty and for eight months after active duty or TRICARE coverage ends, whichever comes first. TRICARE's FAQ says two months before the retirement date to avoid a gap.
• USFHP enrollees from before October 1, 2012. The brochure: anyone enrolled in the Uniformed Services Family Health Plan "on or before Sept. 30, 2012" may stay in it at 65 without Part B. Everyone who enrolled later is disenrolled from USFHP at 65 and moves to TFL, and only with Part A and Part B in hand.
• Already on Medicare because of a disability. Coverage continues without interruption at 65, and a late-enrollment penalty you were paying for Part B is removed when you reach 65.

When to sign up: Medicare's window and TRICARE's

Medicare's Initial Enrollment Period is seven months: the three months before the month you turn 65, that month, and the three after. Sign up before your birthday month and coverage starts the month you turn 65; sign up during the birthday month or the three months after and it starts "the next month." TRICARE wants you ahead of that, because TFL cannot begin until Part B is in effect and TRICARE coverage ends the day it is required. The October 15 notice says to enroll "at least two months before the month you turn 65," and the brochure splits it by birthday:

Two more mechanics from the brochure. If you already receive Social Security or Railroad Retirement benefits and live in the United States, American Samoa, Guam, the Northern Mariana Islands or the U.S. Virgin Islands, Part A and Part B are set up for you automatically at 65. In Puerto Rico you get Part A automatically but must sign up for Part B yourself. And TRICARE mails a notice five months before your 65th birthday; the October 15 notice tells you to read it. You can sign up online with the Social Security Administration or by appointment.

What TFL costs in 2026

TRICARE's side is close to free. Medicare's side is the premium. The table is per person; a retired couple who have both turned 65 pay the Part B line twice.

For a doctor visit covered by both programs, Medicare pays 80 percent and TRICARE pays the other 20 percent, so you pay nothing; TFL also absorbs the extra 15 percent a Medicare non-participating provider may charge above the Medicare allowable. For inpatient days 61 to 90, TRICARE pays the $434 a day Medicare coinsurance, days 91 to 150 $868 a day, and skilled nursing days 21 to 100 $217 a day. Your own money is reached only for care Medicare alone covers (its deductible and 20 percent), care TRICARE alone covers (its deductible and cost-share), chiropractic care (Medicare's 20 percent, TRICARE pays nothing), or care neither covers.

Prescriptions run through the TRICARE Pharmacy Program, which Medicare counts as creditable drug coverage, so Part D is optional. The copays for 2026 and 2027 are fixed by 10 U.S.C. 1074g(a)(6): $16 for a 30-day retail generic, $48 for retail brand, and $14, $44 and $85 for 90-day home delivery generic, brand and non-formulary. Our TRICARE 2027 costs guide has the full table.

The Part B premium by income, per person and per couple

Part B is income-tested on the tax return from two years earlier. These are the 2026 brackets from the CMS fact sheet, with what each tier costs over a year for one person and for a couple filing jointly who both pay it:

That premium comes out of the retired pay you can estimate with the High-3 calculator, and both move with the cost of living: retired pay rises 3.6 percent for 2027, in our retiree COLA guide, while the 2027 Part B premium waits on CMS.

What skipping Part B costs

Decline Part B at 65 and two things happen. TRICARE coverage ends, except that you "can only get your prescriptions filled at military pharmacies." And when you sign up later, Medicare adds "an extra 10% for each year you could have signed up for Part B, but didn't," for as long as you have Part B, which for most people means for life. Medicare's own example is a 24-month wait: a 20 percent penalty on the $202.90 standard premium, $243.50 a month. Medicare rounds the penalty to the nearest 10 cents, which is why its example reads $243.50 rather than $243.48. The table extends that arithmetic at 2026 rates; the penalty is recomputed on each year's new premium, so the real lifetime cost rises with it.

The penalty does not apply when you sign up during a Special Enrollment Period, and the brochure repeats Medicare's rule that group health plan coverage "based on current employment" lets you delay Part B without it. That rule protects you from the penalty, not from the TRICARE rule: a retiree with employer coverage who skips Part B has no TRICARE until Part B is in effect.

TFL against the retiree plans it replaces

Retirees under 65 pay TRICARE enrollment fees. TFL charges none, and its catastrophic cap is the lowest in the retiree system. The 2026 figures below are from the Defense Health Agency's costs and fees preview; Group A means the sponsor first entered service before January 1, 2018, Group B on or after.

A Group B retiree family on Select pays $1,191 a year in enrollment fees under a $4,635 cap. The same two people on TFL pay $0 to TRICARE and $4,869.60 to Medicare at the standard tier under a $3,000 cap. The money moves from TRICARE to Medicare; it does not disappear. Plan it beside the SBP premium and your state's tax on retired pay, the other fixed charges on a retiree's check, and the survivor benefit figures a spouse would inherit.

Overseas, Medicare Advantage and Part D

• Overseas. Medicare pays nothing outside the United States and its territories. TFL then pays first for TRICARE-covered care after the TRICARE deductible, with a 25 percent cost-share for network care, and a nonparticipating provider may bill above the TRICARE allowable. You must keep paying the Part B premium to stay eligible.
• Medicare Advantage. An Advantage plan delivers your Part A and Part B benefits through its own network. TRICARE can reimburse the copayments you pay for TFL-covered services, and you may have to file those claims yourself.
• Part D. Not required. TRICARE's pharmacy benefit is creditable coverage, so there is no Part D late penalty for going without it. The brochure allows that a Part D plan may cover a drug TFL does not; Medicare's drug plan open enrollment runs October 15 through December 7 each year. Beneficiaries living overseas are not eligible for Part D.

The checklist, from TRICARE's own brochure

1. 1Confirm you qualify for premium-free Part A, through your own work record or a current or former spouse age 62 or older. If you do not, TRICARE's FAQ says you must show proof of that to keep TRICARE.
2. 2Sign up for Part A and Part B two to four months before the month you turn 65 if your birthday is the first of a month, otherwise one to three months before, online with Social Security or by appointment.
3. 3Update DEERS. The brochure's step is to take your Medicare Notice of Award to a uniformed services ID card office so your record shows Part A and Part B.
4. 4Read the notice TRICARE mails five months before your birthday, and expect no card and no form from TRICARE: your Medicare card plus your uniformed services ID card are what you show the provider.
5. 5Know the contractor. WPS Government Services pays the TRICARE share of TFL claims after Medicare forwards them.

The bottom line

TFL is the lowest-priced coverage in the retiree system, and the price of admission is Part B: $202.90 a month in 2026 for most retirees, more at higher incomes, and 10 percent more for every year you wait. Sign up before the month you turn 65, keep DEERS current, and the rest is automatic. Rates shown are calendar year 2026 Medicare figures and the 2026 TRICARE figures; verify your own case with WPS, the Social Security Administration or your finance office.