As with the earlier 3M version for the USAF, the new version was re-engined with newer Garrett turboprops (now Honeywell TPE331) which offered more power (flat rated to 1,020 shp/760 kW with a thermodynamic limit of 1,100 shp/820 kW) and longer overhaul intervals over the original Turbomeca Astazou engines.

This allowed the aircraft to be offered in an 18-seat option (six rows, 2+1), with an offset aisle, and with a water methanol option for the engine to allow the ability to operate at maximum load from a greater range of airfields, particularly in the continental United States and Australia.

The new version proved to be as popular as Handley Page hoped the original model would be, and several hundred 31s were built during the 1980s.

In 1993, British Aerospace adopted the Jetstream name as its brand name for all twin turboprop aircraft.

[2] In July 2019, 70 Jetstream 31s were in airline service: 49 in the Americas, 15 in Europe, 5 in Asia-Pacific and 1 in Africa.