Having been displaced by the newer 221 series, from 1990 many of 117 series cars had been transferred to the Fukuchiyama Line.
These cars retained their original numbers, but had 300 appended to them.
Through 1992, 1993, and 1995, a total of 58 cars were refurbished and reassigned to JR-West's Miyahara Depot.

In order to increase the capacity of the cars and make boarding and alighting easier, transverse seating immediately inside the doors was converted to longitudinal seating.
This helped to reduce the problem of rush hour trains being delayed due to the time needed for passengers to board and alight.
Brakes were augmented, and the livery associated with the Fukuchiyama Line, white with green striping, appeared.

However, these modifications did not entirely solve the problems with passenger mobility during rush hour, and as a result, the 117-300s were used on outgoing services (bound for Fukuchiyama) and off-peak services.
From April 2000, two 4-car sets were dispatched from Hineno Depot for operation on the Wakayama Line and the Kisei Main Line.

Sets which remained on the Fukuchiyama Line until the series' complete withdrawal from the line are now assigned to Kyoto Depot for operation on the Sanin Main Line (Sagano Line), Kosei Line, and Kusatsu Line.
Some sets have ATS-P train control on board, others have MoHa cars made surplus by the creation of the shorter 100 sub-series sets.

300 sub-series renumbering
MoHa117/116-3 – 16, 19, 20, 41, 42 → MoHa117/116-303, 316, 319, 320, 341, 342
KuHa117/116-2 –  8, 10, 18, 20, 10 → KuHa117/116-302, 308, 310, 318, 320, 321
Having been displaced by the newer 221 series, from 1990 many of 117 series cars had been transferred to the Fukuchiyama Line. These cars retained their original numbers, but had 300 appended to them. Through 1992, 1993, and 1995, a total of 58 cars were refurbished and reassigned to JR-West's Miyahara Depot.
In order to increase the capacity of the cars and make boarding and alighting easier, transverse seating immediately inside the doors was converted to longitudinal seating. This helped to reduce the problem of rush hour trains being delayed due to the time needed for passengers to board and alight. Brakes were augmented, and the livery associated with the Fukuchiyama Line, white with green striping, appeared.
However, these modifications did not entirely solve the problems with passenger mobility during rush hour, and as a result, the 117-300s were used on outgoing services (bound for Fukuchiyama) and off-peak services. From April 2000, two 4-car sets were dispatched from Hineno Depot for operation on the Wakayama Line and the Kisei Main Line.
Sets which remained on the Fukuchiyama Line until the series' complete withdrawal from the line are now assigned to Kyoto Depot for operation on the Sanin Main Line (Sagano Line), Kosei Line, and Kusatsu Line. Some sets have ATS-P train control on board, others have MoHa cars made surplus by the creation of the shorter 100 sub-series sets.
300 sub-series renumbering
MoHa117/116-3 – 16, 19, 20, 41, 42 → MoHa117/116-303, 316, 319, 320, 341, 342
KuHa117/116-2 –  8, 10, 18, 20, 10 → KuHa117/116-302, 308, 310, 318, 320, 321
117 series