The 731 series (731系) is an AC electric multiple unit (EMU) train type operated by Hokkaido Railway Company (JR Hokkaido) on Sapporo area suburban services in Hokkaido, Japan since 1996.

[2] As of 1 October 2016[update], 21 three-car sets are in service, numbered G-101 to G121, and based at Sapporo Depot.

[3] Seating consists of longitudinal bench seating throughout, without the vestibule areas used on the earlier 721 series trains.

[2] A total of 63 vehicles (21 sets) were delivered to Sapporo Depot between 1996 and 2006.

[4] From the start of 22 March 1997 timetable revision, 731 series EMUs were operated in multiple with KiHa 201 series DMU sets over certain routes.