Is Tricare Prime considered a group health insurance plan or an individual health insurance plan for retired military?

Tricare Prime is not a "stand alone" plan. Tricare Prime is TRICARE Prime Supplemental Insurance Plan de¬signed to help pay your cost share and copayments under TRICARE (In-Network and Out-of-Network expenses). It was modeled as an HMO.

Your Tricare Standard/Extra Plan is the base coverage.