J-K3S, the single-seat variant of the J-K3, is a quasi-fourth-generation fighter. Its armament differs slightly from the J-K3, with the K3S prioritizing beyond-visual-range (BVR) combat over delivering bombs directly onto enemy positions.

The aircraft's cannons have been modified, upgrading from the original 20mm to 37mm caliber, while retaining nearly identical fire control systems from the J-K3.

Though its airframe strength remains unchanged from the K3, the J-K3S carries substantial cannon ammunition but fewer missiles. This configuration may force pilots into close-quarters dogfights during prolonged engagements, where the cannon's generous ammunition capacity proves crucial.

Notably, this aircraft is not carrier-based — don't even think about hastily deploying it on an aircraft carrier without modifications.