Model Variants (Including Prototypes)
G-21 - Initial Production Model; seating for six passengers; 12 examples produced.
G21A - Improved version; increased weight; 30 examples produced.
G-21B - Export Armed Patrol Variant; fitted with 2 x 0.30 caliber machine guns and provision for 2 x bombs; Portuguese Navy service; 12 examples delivered.
G-21C - McKinnon Conversion Model; 4 x Lycoming GSO-480 supercharged engines of 340 horsepower; various modifications.
G-21D "Turboprop Goose" - McKinnon Conversion Model; lengthened bow; additional passenger windows and increased passenger seating; fitted with 2 x Pratt & Whitney Canada PT6A-20 turboprop engines of 550 horsepower.
G-21E - McKinnon Conversion Model; 2 x Pratt & Whitney Canada PT6A-20 engines of 550 horsepower; increased fuel stores; single example.
G-21F - McKinnon Conversion Model; Alaska Fish and Wildlife version based on McKinnon information; fitted with 2 x Garrett TPE331 series turboprop engines of 715 horsepower.
G-21G "Turbo-Goose" - McKinnon Conversion Model; final McKinnon offering; fitted with 2 x Pratt & Whitney Canada PT6A-27 series engines of 680 horsepower; 2 examples completed.
XJ3F-1 - US Navy prototype; single example
JRF-1 - Initial US Navy production model based on the XJ3F-1 prototype; 5 examples produced.
JRF-1A - Based on the JRF-1; completed with camera facilities and target tow installation; 5 examples produced.
JRF-2 - USCG variant of the JRF-1; room for medical litters; 7 examples completed.
JRF-3 - Based on JRF-2 model; USCG use; completed with autopilot and wing deicing feature; 3 examples.
JRF-4 - Based on JRF-1A; USN use; provision for depth charges to be held underwing; 10 examples produced.
JRF-5 - Definitive production mark; provision for bombs; installation of camera gear and target tow system; wing deicing system; 184 examples produced.
JRF-5G - USCG version of JRF-5 model borrowed from USN; 24 examples.
JRF-6B - Lend-Lease Export Trainer; 50 examples; used in navigational training by RAF in Caribbean.
OA-9 - USAAF transport or air-sea rescue platform; 26 examples later joined by 5 JRF-6B mounts sharing same designation.
OA-13A - G-21A civilian models commandeered by USAAF for wartime use; 3 examples.
OA-13B - JRF-5 in USAAF service; 2 examples transferred.
Goose Mk I - British Designation of JRF-5; 3 examples.
Goose Mk IA - British Designation of JRF-6B trainers; 44 examples.
Goose Mk II - British Designation of JRF-5 for VIP military transport; 2 examples.
Grumman LXG - One-off example evaluated by IJN; never procured.