The station is composed of two side platforms on an overhead railway. Elevators to connect platforms and concourse is set in March 2009. The station name contains "Ōmori", which usually indicates a part of the Ōta ward, but the actual location of much of the station is Shinagawa ward.
On 1 February 1901, the station was opened as Yawata Station (八幡駅) when the Keihin Electric Railway extension line from Kawasaki to Ōmori Teishajōmae (by Ōmori Station) commenced the service. On 8 May 1904, the main line was extended from this station, concurrently renamed as Kaigan Station (海岸駅), to Shinagawa, making the station a junction of the main line and a branchline to Ōmori Teishajōmae. The branchline was active until 8 March 1937.[3]
The current station name Ōmorikaigan is from 1 July 1933. On 1 December 1970, the work to move the station to the elevated line was completed.[citation needed]
Keikyu introduced station numbering to its stations on 21 October 2010; Ōmorikaigan was assigned station number KK07.[4]
^"京急線全駅にて駅ナンバリングを開始します" [Station numbering will be introduced to all stations on the Keikyu Line]. KEIKYU WEB. 25 June 2010. Archived from the original on 21 February 2014. Retrieved 27 February 2023.