Medicare 2026

TRICARE and Medicare Before 65: How Part B Fits In When Disability or Kidney Failure Starts the Clock

Most people think of Medicare as something that arrives at 65. But for people receiving Social Security Disability Insurance (SSDI) or living with end-stage renal disease (ESRD), Medicare can start much earlier — and when you also have TRICARE, the question of whether to take Part B is not optional for most retiree families. Here is how the pieces fit together.

When Medicare starts before 65

Two paths bring people under 65 into Medicare. The first is SSDI: after 24 months of SSDI payments, Medicare begins in the 25th month, and the Social Security Administration mails a notice with the exact start date. The second is ESRD, which has its own timing rules tied to dialysis or a transplant.

Either path gives you premium-free Part A if your work history (or a spouse's or parent's) qualifies. Part B, which covers doctor visits and outpatient care, carries a monthly premium. CMS announces the standard Part B premium and deductible for the following year in the fall, usually in November, so the 2027 figures are not yet available. The same is true for the income-related monthly adjustment amounts (IRMAA) that higher earners pay.

Why Part B matters so much for TRICARE retirees

TRICARE has a firm rule for retirees and their family members: if you are entitled to premium-free Part A, you must also have Part B to remain TRICARE-eligible. That rule applies regardless of age and regardless of whether Medicare began because of disability or ESRD.

Here is the good news for younger retirees: having Part A and Part B under 65 does not push you out of TRICARE Prime or the Uniformed Services Family Health Plan (USFHP). You may stay enrolled in Prime until 65 as long as you remain eligible. For Group A enrollees — those whose sponsor's service began before January 1, 2018 — the TRICARE Prime enrollment fee may be waived while you are Medicare-eligible under 65. The waiver does not apply to Group B. Anyone who does not enroll in Prime or USFHP is automatically covered by TRICARE For Life.

The Part B Special Enrollment Period for TRICARE beneficiaries

CMS recognizes that many TRICARE families don't sign up for Part B when first eligible because they already have coverage. To avoid trapping them, CMS offers a Part B Special Enrollment Period (SEP) for people who:

• are under 65,
• were eligible for TRICARE when their Part A began,
• have Part A based on disability or ESRD,
• are military retirees or retiree family members, and
• did not enroll in Part B because they had TRICARE.

According to Medicare.gov, this SEP starts when Social Security notifies the person and ends 12 months later. No Part B late enrollment penalty applies. Enrolling promptly is the safest way to avoid a gap in TRICARE.

Disability awarded on appeal

If a retiree or retiree family member is awarded disability on appeal and the Part B effective date is October 2009 or later, there is no requirement to buy Part B retroactively back to the Part A effective date. However, you must carry Part B from its original effective date going forward to keep TRICARE in place.

Active-duty families and ESRD

Rules for active-duty service members and active-duty family members differ. If Medicare eligibility is based on ESRD, Part B is not required to keep TRICARE. These families also do not get the TRICARE Part B SEP that other Medicare-eligible active-duty families receive, so TRICARE strongly encourages them to enroll in Part B when first eligible to avoid later penalties and gaps.

Reserve plans and USFHP

Enrollees in TRICARE Reserve Select, TRICARE Retired Reserve, and USFHP who are entitled to premium-free Part A are not required to have Part B to keep those plans. Still, TRICARE encourages Part B enrollment at first eligibility because being in Reserve Select or Retired Reserve does not qualify you for a Medicare Special Enrollment Period later.

If SSDI ends because you return to work

Medicare coverage can continue for up to eight and a half years after SSDI payments stop due to returning to work. During that extended period, you receive a quarterly bill for the Part B premium. If the premium goes unpaid, both Part B and your TRICARE coverage end — a costly result that is easy to prevent by keeping the quarterly payments current.

Part D drug coverage considerations

TRICARE includes prescription drug coverage that is generally considered creditable, so most TRICARE-eligible people do not need a separate Medicare Part D plan. If you do consider Part D, program-wide changes for 2027 include a $2,400 annual out-of-pocket cap on covered drugs, a maximum plan deductible of $700, and a national base beneficiary premium of $41.33 used in the late-enrollment penalty calculation (actual plan premiums are set plan by plan). The Annual Enrollment Period for 2027 coverage runs October 15 – December 7, 2026, with changes effective January 1, 2027. Social Security announced a 3.6 percent cost-of-living adjustment for benefits payable beginning January 2027.

Weighing your coverage choices

Some retirees pair Medicare with TRICARE For Life and stop there. Others look at Medicare Advantage or Original Medicare with a Medigap policy. Each path has trade-offs — network rules, cost-sharing structure, referral requirements, travel coverage, and how it coordinates with TRICARE. There is no single right answer; the best fit depends on your household, your providers, and your preferences.

Where to go for help

For official enrollment windows, current figures as they are announced, and personalized account information, visit Medicare.gov or call 1-800-MEDICARE (1-800-633-4227), available 24 hours a day, 7 days a week. For TRICARE-specific questions, contact your regional TRICARE contractor.