Minatomirai Line

The corridor's origins lie in Yokohama's post-war planning. In 1965 the redevelopment of what would become the Minatomirai district was put forward as one of the city's "Six Great Projects," together with a municipal subway scheme, although at that stage no line corresponding to the present Minatomirai Line had yet been conceived. The following year the Urban Transport Council's Report No. 9 proposed a Line 3 running from Honmoku through Kannai, Sakuragichō, Yokohama and Shin-Yokohama to Katsuta; the Honmoku–Yokohama portion of that proposal corresponds to today's Minatomirai Line, and in October 1966 the Yokohama city assembly resolved to build municipal subway lines 1 to 4.

The route was first pursued as a city-run subway. On 7 March 1967 the Yokohama Transportation Bureau obtained a railway licence for Municipal Subway Line 2, running from Kitasaiwaichō (at Yokohama Station) to Yamashitachō, the stretch that prefigured the Minatomirai Line. In 1973 the planned alignment was altered to run from Onoechō, near Kannai Station, to Yamashitachō close to the later Motomachi-Chūkagai Station, but objections from the Honmoku port industry over construction-related traffic congestion led the transport minister to suspend approval of the works.

The modern project took shape in the 1980s. The Transport Policy Council's Report No. 7 of 11 July 1985 designated a "Minatomirai 21 Line" — from Higashi-Kanagawa through the Minatomirai 21 district to the vicinity of Motomachi — as a section that should appropriately be opened by a target year of 2000, and it is from this report that the line takes its formal name. In June 1987 the Kanagawa Shimbun broke the news of a plan to through-run with the Tōkyū Tōyoko Line. The Yokohama Minatomirai Railway Company was established on 29 March 1989, and on 19 April 1990 it obtained a first-class railway business licence; on the same day the licence for the competing Municipal Subway Line 2 was abolished.

Construction proceeded in two phases. Approval for the first-phase section, from the future Minatomirai station to Motomachi, was granted in November 1991, and a groundbreaking ceremony followed on 24 November 1992; English-language sources date the start of construction to 1993. Approval for the second-phase section, from Yokohama to Minatomirai, came in October 1994, with its groundbreaking in February 1995. The official station names were settled on 16 December 2002, and on 9 July 2003 the company announced that the line would open on 1 February 2004 with reciprocal through service, adopted a symbol mark, and unified the line's branding under the abbreviated name "Minatomirai Line."

The Minatomirai Line opened on 1 February 2004, beginning reciprocal through operation with the Tōkyū Tōyoko Line the same day. Patronage built quickly: cumulative ridership reached 100 million on 14 April 2006 and 300 million on 22 October 2009. The line's through-running network widened on 16 March 2013, when service via the Tokyo Metro Fukutoshin Line linked it with the Tōbu Tōjō Line and the Seibu Yūrakuchō and Ikebukuro lines, extending one-seat journeys far beyond Yokohama. Around the same period, tunnel deformation was identified between Yokohama and Shin-Takashima, prompting ground-improvement and reinforcement works from 2012.

In its second decade the line has been steadily modernised. Platform edge doors began operating at Yokohama Station in March 2015 and were completed at every station by 6 November 2021. On 6 June 2020 Bashamichi Station gained the subsidiary name "Yokohama City Hall" after the municipal government relocated nearby, and on 18 March 2023 the line introduced driver-only (one-man) operation. From 4 December 2024 the operator began trialling contactless credit-card and QR-code ticketing at all stations, and from 22 July 2025 a paid reserved-seat "Q Seat" service was offered on some evening Tōyoko-bound express trains.

• 1965The redevelopment of the future Minatomirai district and a municipal subway scheme are proposed as part of Yokohama's "Six Great Projects," though no line equivalent to today's Minatomirai Line yet exists.
• 196615 July: Urban Transport Council Report No. 9 proposes a Line 3 from Honmoku via Kannai, Sakuragichō, Yokohama and Shin-Yokohama to Katsuta; the Honmoku–Yokohama portion corresponds to today's Minatomirai Line. In October the city assembly resolves to build municipal subway lines 1–4.
• 19677 March: the Yokohama Transportation Bureau obtains a railway licence for Municipal Subway Line 2 (Kitasaiwaichō, at Yokohama Station, to Yamashitachō), the precursor of the Minatomirai Line.
• 19736 September: the planned alignment of Line 2 is changed to run from Onoechō (near Kannai Station) to Yamashitachō; objections from the Honmoku port industry over traffic congestion lead the transport minister to suspend approval of construction.
• 198511 July: Transport Policy Council Report No. 7 designates a "Minatomirai 21 Line" (Higashi-Kanagawa–Minatomirai 21 district–vicinity of Motomachi) as suitable for opening by a target year of 2000; the line's formal name derives from this report.
• 198711 June: the Kanagawa Shimbun reports, as a scoop, a plan to through-run with the Tōkyū Tōyoko Line.
• 198929 March: the Yokohama Minatomirai Railway Company is established.
• 199019 April: the company obtains a first-class railway business licence; the same day, the licence for the competing Municipal Subway Line 2 is abolished.
• 199224 November: groundbreaking ceremony for the first-phase section (future Minatomirai station to Motomachi), approved in November 1991. English-language sources date the start of construction to 1993.
• 1995February: groundbreaking for the second-phase section (Yokohama to Minatomirai), approved in October 1994.
• 200216 December: the official station names are decided — from Yokohama: Shin-Takashima, Minatomirai, Bashamichi, Nihon-Ōdōri and Motomachi-Chūkagai.
• 20039 July: the company announces a 1 February 2004 opening with reciprocal through service, adopts a symbol mark, and unifies the line's branding under the abbreviated name "Minatomirai Line."
• 20041 February: the Minatomirai Line opens, beginning reciprocal through operation with the Tōkyū Tōyoko Line the same day.
• 200922 October: cumulative ridership reaches 300 million, having passed 100 million on 14 April 2006.
• 201316 March: through service via the Tokyo Metro Fukutoshin Line begins, linking the line with the Tōbu Tōjō Line and the Seibu Yūrakuchō and Ikebukuro lines.
• 20216 November: platform edge doors are completed at every station (operation having begun at Yokohama Station in March 2015).
• 202318 March: driver-only (one-man) operation begins on the line.