Glossary
Medicare Part B
The medical insurance side of Original Medicare — covers doctor visits, outpatient care, preventive services, and durable medical equipment.
Also known as: Medical Insurance, Part B, SMI, Supplementary Medical Insurance
Quick answer
Medicare Part B is the medical insurance component of Original Medicare. It covers physician services, outpatient hospital care, preventive screenings, lab work, durable medical equipment (DME), ambulance transport, and many other outpatient services. Unlike Part A, Part B has a monthly premium for everyone.
Why it matters
Part B is the single most important piece of the Medicare puzzle for retired military. **Without Part B, you lose TRICARE For Life.** The Defense Health Agency requires both Parts A and B to remain enrolled to keep TFL active at any age you're eligible for Medicare.
When you'll encounter it
You enroll during your Initial Enrollment Period (3 months before, the month of, and 3 months after your 65th birthday). If you're already on Social Security, Part B starts automatically but you may decline it — do not decline if you want to keep TFL.
Impact on Medicare
Part B pays 80% of the Medicare-approved amount for most covered services after you meet the annual Part B deductible. You're responsible for 20% coinsurance and the deductible.
Impact on TRICARE For Life
TFL becomes your secondary payer for Part B services. For services covered by both Medicare and TRICARE at a Medicare-participating provider, TFL typically pays the 20% coinsurance and deductible — leaving you with $0 out-of-pocket.
Impact on Medicare Advantage
A Medicare Advantage plan replaces how Original Medicare delivers Part B benefits — you still pay the Part B premium to Medicare, but the plan administers your care. Many veteran-focused MA plans include a 'Part B giveback' that reduces what's deducted from your Social Security check.
VA Healthcare considerations
VA Healthcare is not creditable coverage for Part B late-enrollment purposes. Even if you receive 100% of your care at a VA facility, declining Part B at 65 will cost you TRICARE For Life and trigger a permanent Part B late penalty if you ever need to re-enroll. Many retirees enroll in Part B to keep TFL as a safety net for non-VA emergencies, travel, and family care.
Military-specific context
The Part B premium ($202.90 standard in 2026) feels like a new expense, but the value is enormous: it activates TRICARE For Life — typically a $0 secondary — and gives you nationwide access to any Medicare-accepting provider. A single hospitalization without Part B/TFL can easily exceed a decade of Part B premiums.
Common misconceptions
- "TRICARE counts as creditable coverage so I can skip Part B without a penalty." — Wrong. TRICARE does not qualify as employer group coverage for a Special Enrollment Period. Skipping Part B triggers permanent late penalties AND terminates your TFL.
- "Part B is optional once I'm retired." — It is technically optional, but declining it ends your TRICARE For Life coverage.
Common mistakes to avoid
- Declining Part B at 65 because 'I'll just use the VA' — this terminates TFL permanently and triggers late penalties.
- Letting Part B lapse for non-payment of premium — TFL terminates immediately when Part B does.
- Assuming high income means you can't afford Part B — IRMAA appeals (SSA-44) can drastically reduce surcharges after retirement.
- Not budgeting for the Part B premium being deducted from Social Security before it starts.
Real-world scenario: A retired Navy captain declines Part B at 65 to save the premium, planning to rely on VA care.
His TRICARE For Life terminates on his 65th birthday. Six months later he is hospitalized while traveling. The VA does not cover the civilian hospital bill, and without Part B/TFL he is fully responsible. When he re-enrolls during the next General Enrollment Period, his Part B premium carries a permanent 20% late penalty for life.
Questions people commonly ask
- Do I really need Medicare Part B if I have TRICARE?
- What happens if I don't sign up for Part B at 65?
- Can I drop Part B later if I change my mind?
- Does VA care count as creditable coverage for Part B?
- How is the Part B premium paid?
Continue learning
— suggested by the knowledge graph- Appointment of RepresentativeA signed form (CMS-1696) that authorizes another person — family member, attorney, or advocate — to file or pursue a Medicare appeal on your behalf.
- Benefit Period (Part A)The Part A timeframe used to measure hospital deductibles and coinsurance — it resets after 60 days out of the hospital.
- Creditable CoverageNon-Medicare coverage that CMS deems at least as good as a standard Medicare Part D plan — TRICARE Pharmacy qualifies, so TFL beneficiaries don't need Part D.
- Creditable Drug CoveragePrescription drug coverage that CMS certifies is at least as good as standard Medicare Part D — including TRICARE Pharmacy and VA Pharmacy.
- Disability Medicare Eligibility (Under 65)Medicare eligibility before age 65 — automatic after 24 months of SSDI, immediately for ALS, and based on dialysis/transplant for ESRD.
- Durable Medical Equipment (DME)Medically necessary, reusable equipment for home use — covered by Part B at 80% after the deductible.
- End-Stage Renal Disease (ESRD)A condition (permanent kidney failure requiring dialysis or transplant) that grants Medicare eligibility at any age.
- General Enrollment Period (GEP)The January 1 – March 31 window each year when you can sign up for Medicare if you missed your IEP and don't qualify for an SEP.
- What is the Initial Enrollment Period (IEP)?The 7-month window around your 65th birthday — 3 months before, your birthday month, and 3 months after — when you first enroll in Medicare without penalty.
- I'm still working past 65. Can I delay Part B?Only if you have true employer group health coverage from active employment (yours or your spouse's, 20+ employees). In that case you get a Special Enrollment Period later. But TFL won't activate until you take Part B.
- I missed my Medicare enrollment window. Now what?Use the General Enrollment Period (Jan 1 – Mar 31). You'll likely owe a Part B late penalty for life, and you'll have no TFL until Part B is effective.
- What is the General Enrollment Period?January 1 – March 31 each year. It's the backup enrollment window for people who missed their IEP and don't qualify for a Special Enrollment Period.
- Do I need Medicare Part A if I have TRICARE?Yes. TFL requires Part A and Part B. Part A is typically premium-free if you or your spouse worked 40+ quarters paying Medicare taxes.
Related glossary terms
Related Official Resources
Continue learning straight from the source. Every link below goes to an official government or DoD resource.
Last reviewed January 2026 against the 2026 Medicare & You and TRICARE For Life handbooks.