O2U-1 two prototypes and 130 production aircraft with interchangeable wheel/float landing gear, Pratt & Whitney 336-kW (450-hp) R-1340-88 Wasp engine. Had one forward-firing and two 7.62- mm (0.3-in) machine-guns on trainable mount in rear cockpit.

O2U-2: version with increased-span upper wing and wing refinements, larger rudder and R-1340-B engine; 37 were built, 31 for U.S. Navy, and 6 for the U.S. Coast Guard .

O2U-2M an O2U-2 built for Mexico

O2U-3   an O2U-2 with revised wing rigging, redesigned tail surfaces and R-1340-C engine; 80 were built.

O2U-3SD an O2U-3 built for Santo Domingo

O2U-4 an O2U-3 but with changes of equipment; 42 were built.