[2][3] Similar in appearance to the aluminium-bodied 735 series EMUs built in 2010, the 733 series EMUs have stainless steel bodies with steel driving cab ends.

[4][5] As of 1 October 2015[update], the fleet consists of 21 three-car sets, numbered B-101 to B-121, and seven six-car 733-1000 series sets, numbered B-3101 to B-3107, formed as shown below, with one motored ("M") intermediate car and two non-powered trailer ("T") cars.

[6] The fleet of four three-car 733-1000 series sets are formed as shown below, with car 1 at the Hakodate end.

[14] The first two 733-1000 series three-car sets, B-1001 and B-1002, were delivered from the Kawasaki Heavy Industries factory in Kobe in October 2015.

[15] The first two 733-4000 series six-car sets, B-4101/4201 and B-4102/4102, were delivered from the Kawasaki Heavy Industries factory in May 2024.