Yokohama Line services are operated using a fleet of 8-car 205 seriesEMUs, first introduced in 1988. The second car from the Higashi-Kanagawa end has six pairs of doors on each side to allow rapid boarding and disembarking during peak periods. Through trains to and from the Sagami Line are served by 4-car 205-500 series EMUs.
New 8-car E233-6000 series EMUs were introduced on Yokohama Line services from 16 February 2014, with a fleet of 28 sets scheduled to replace the 205 series EMUs by the summer of the same year.
A Yokohama Line 103 series at Higashi-Kanagawa Station marking the first anniversary of JR East, April 1988
The line was opened by the private Yokohama Railway (横浜鉄道,Yokohama Tetsudō?) on 23 September 1908 and leased to the government in 1910. The line was nationalized in 1917.
Only part of the route was double-tracked prior to 1967, when the Kikuna – Shin-Yokohama section was double-tracked. In 1988 the Aihara –Hachiōji section was double-tracked, eliminating all single-track sections from the line.