The is a 14.3 km Japanese railway line operated by the third-sector railway operator between and , all within Hitachinaka, Ibaraki. It is the only railway line operated by the Hitachinaka Seaside Railway. The line was formerly operated by Ibaraki Kà Âtsà « until 2008.
The was established on 18 November 1907, and the line was opened from Katsuta to Nakaminato on 25 December 1913, using steam haulage. The entire line to Ajigaura was completed on 17 July 1928. From 1 August 1944, the line was taken over by , becoming the Ibaraki Kà Âtsà « Minato Line.
The Minato Line was the only railway line operated by Ibaraki Kà Âtsà «, whose main business was bus transport. Because of its severe financial situation, Ibaraki Kà Âtsà « decided to withdraw from railway operation. In September 2007, Ibaraki Kà Âtsà « and the city of Hitachinaka agreed to transfer the line to a third-sector (funded jointly by local government and private sector) company, later incorporated as Hitachinaka Seaside Railway. From 1 April 2008, the line became the Hitachinaka Seaside Railway Minato Line.
From 6 April 2010, all train services became one-man operation.
The line was damaged by the 11 March 2011 Great East Japan earthquake, but the entire line was reopened for business from 23 July of the same year. The line is planned to be extended north by in the future. The two stations will be near the southern gate and the western gate of the Hitachi Seaside Park. As of 2025, these stations are assigned tentative names New Station 1 and New Station 2.
Train services are normally formed of single-car diesel units, increased to two-car formations during the morning peak.
, the railway operates a fleet of eight single-car diesel railcars, as follows.
In April 2015, three former JR Central KiHa 11 diesel cars, KiHa 11-123/203/204, were sold to the Hitachinaka Kaihin Railway, becoming KiHa , Kiha , and KiHa respectively. Two more KiHa 11-200 series cars, formerly owned by Tokai Transport Service Company (TKJ) in Aichi Prefecture, were purchased by the Hitachinaka Kaihin Railway in 2015 and 2016. Of these, KiHa 11-201 was moved by road to the Hitachinaka Kaihin Railway in September 2015, and Kiha 11-202 was moved in March 2016.
One of them is scheduled to be converted to a sightseeing train.
KiHa 2004 was withdrawn from service in December 2015, and sold to the Heisei Chikuhà  Railway in Kyushu in 2016.