Model Variants (Including Prototypes)
H8K1 - Prototype
H8K1 (Navy Flying Boat Type 2, Model 11) - 14 produced; initial service models.
H8K1-L - Dedicated Transport Variant
H8K2 (Model 12) - Improved engine output through Mitsubishi Kasei 22 radials of 1,850 horsepower and defensive armament; ASW radar equipped; 120 produced.
H8K2-L "Seiku" (Model 32) - Dedicated Transport Variant based on the H8K1 model.
H6K3 - Two prototype experimental models based on the H8K2; featuring retractable wingtip floats and dorsal turret; blisters removed in favor of sliding gun hatches.
H8K4 (Model 23) - Two conversion models fitted with different powerplants.