The Hokkaido Shinkansen (北海道新幹線, Hokkaidō Shinkansen) is a Japanese high-speed Shinkansen rail line that links up with the Tōhoku Shinkansen in northern Aomori Prefecture in Honshu and continues on into the interior of Hokkaido through the undersea Seikan Tunnel. Construction started in May 2005; the initial Shin-Aomori to Shin-Hakodate-Hokuto section opened on 26 March 2016. The section of the line to Sapporo is scheduled to open by fiscal year 2030. The line is operated by the Hokkaido Railway Company (JR Hokkaido).
 In preparation for the opening of the Hokkaido Shinkansen, the Seikan Tunnel (Kaikyō Line) and associated approaches (approximately 82 km or 51 mi in total) were converted to dual gauge, with both the Shinkansen 1,435 mm (4 ft 8+1⁄2 in) standard and 1,067 mm (3 ft 6 in) narrow gauge tracks.
 Upon the opening of the Shinkansen line the section of the conventional (narrow gauge) Esashi Line approximately paralleling the same route between Goryōkaku and Kikonai was transferred from the control of JR Hokkaido to a newly established third-sector railway operating company, South Hokkaido Railway Company, becoming the Isaribi Line.
 Two train service types operate on the Hokkaido Shinkansen: limited-stop Hayabusa services between Tokyo or Sendai and Shin-Hakodate-Hokuto, and semi-fast Hayate services between Morioka or Shin-Aomori and Shin-Hakodate-Hokuto.
 Under the initial timetable, ten return Hayabusa services operate daily between Tokyo and Shin-Hakodate-Hokuto and one return service operates daily between Sendai and Shin-Hakodate-Hokuto. One return Hayate service operates daily between Morioka and Shin-Hakodate-Hokuto, and one return service daily operates between Shin-Aomori and Shin-Hakodate-Hokuto.
 Upon commencement of services in 2016 the maximum speed on the approximately 82 km (51 mi) dual gauge section of the Hokkaido Shinkansen (including through the Seikan Tunnel) was 140 km/h (85 mph), increased to 160 km/h (99 mph) in March 2019. There are approximately 50 freight trains using the dual gauge section each day, so limiting the travel of such trains to times outside of Shinkansen services is not an option. Because of this and other weather-related factors cited by JR East and JR Hokkaido, the fastest journey time between Tokyo and Shin-Hakodate-Hokuto is currently 3 hours, 57 minutes.
 During the 2020-21 New Year Holiday period when fewer freight trains were operating, certain Shinkansen services were operated at 210 km/h (130 mph) on the dual gauge section and this is proposed again for the Golden Week Holiday period from 3–6 May 2021 
 To achieve the full benefit of Shinkansen trains travelling on the dual gauge section at 260 km/h (160 mph) (the maximum speed proposed through the tunnel), alternatives are being considered, such as a system to automatically slow Shinkansen trains to 200 km/h (125 mph) when passing narrow-gauge trains, and/or loading freight trains onto special "Train on Train" standard-gauge trains (akin to a covered piggyback flatcar train) built to withstand the shock wave of oncoming Shinkansen trains traveling at full speed. This would enable a travel time from Tokyo to Shin-Hakodate-Hokuto of 3 hours and 45 minutes, a saving of 12 minutes on the current timetable.
 In May 2019, JR Hokkaido announced that it had requested permission from the MLIT to increase the speed limit on the 212 km (132 mi) of new track to be constructed between Shin-Hakodate-Hokuto and Sapporo to 320 km/h (200 mph). This would involve the extension of buffers on about 170 km (110 mi) of tunnels, installation of sound barriers on about 30 km (19 mi) of the remaining 42 km (26 mi) of surface track and strengthening of viaducts.
 Operating in areas that see significant snowfall during the winter months, accumulation of snow has effects on various train operations. It can cause damage to equipment or can cause a moving train to miss a switch. In particular, accretion of snow in the bogies of the train has been shown to be significant, causing damage or causing schedule delays. Methods have been used to estimate snow accumulation on trains running up to 130 km/h (81 mph), and newer estimates based on weather data can predict accumulation of up to 3 cm (1.2 in) in bogies upon arrival at a station.
 The winter season also adversely impacts the occupancy rates of the rail line, with recorded occupancy reaching a low of 19% in the months of January and February.
 Legend:
 All services are formed of 10-car JR East E5 or JR Hokkaido H5 series trainsets.
 In February 2014, JR Hokkaido placed an order for four 10-car H5 Series Shinkansen trainsets for use on Hokkaido Shinkansen services from March 2016. Based on the E5 series trainsets operated by JR East since 2011, the order for 40 vehicles cost approximately 18 billion yen. The first two sets of the order are scheduled to be delivered to Hakodate Depot by road from Hakodate Port in October 2014, with test running commencing before the end of the year. The remaining two sets on order were scheduled to be delivered in 2015. The vehicles feature the usual upper green and lower white livery, with a purple stripe in the middle. The color purple was chosen to represent the purple flowers of Hokkaido: lilacs, lupine and lavender. Inside, the ordinary-class cars feature wood paneling and carpet with a snowflake motif. Green class features cream-colored walls representing the local dairy industry and carpet with a drift-ice motif. Gran class features dark blue carpets, said to be modeled after the shimmering lakes and bodies of water along the route.
 In the early 1970s, two other Shinkansen routes were proposed for Hokkaido: Sapporo – Asahikawa (Hokkaido Shinkansen extension) and Oshamambe – Muroran – Sapporo (Hokkaido South Route). There were also further unofficial plans to connect to Abashiri, Kushiro and Nayoro/Wakkanai. These plans have been indefinitely shelved.
 On 1 November 2014, a ceremony was held at Kikonai Station to mark the completion of track-laying for the line between Shin-Aomori and Shin-Hakodate-Hokuto. Test-running on the Hokkaido Shinkansen tracks within Hokkaido commenced from 1 December 2014, initially at low speeds, with the speed raised to the maximum of 260 km/h (160 mph) later that month. Test-running was extended through the Seikan Tunnel to Oku-Tsugaru-Imabetsu in December 2014. Test-running south of Oku-Tsugaru-Imabetsu commenced on 21 April 2015, with the first train reaching Shin-Aomori Station from the north in the early hours of 24 May.
 JR Hokkaido is extending the Hokkaido Shinkansen from Shin-Hakodate-Hokuto to Sapporo, planned to open by 2030. Tunneling work on the 5,265 m (3.272 mi) Murayama Tunnel, situated about 1 kilometer (0.6 mi) north of Shin-Hakodate-Hokuto station commenced in March 2015; it is scheduled to be completed by March 2021. The 211.3 km (131.3 mi) extension will be approximately 76% in tunnels, including major tunnels such as Oshima (26.5 km or 16.5 mi), Teine (18.8 km or 11.7 mi) and Shiribeshi (18 km or 11 mi).
When the section to Sapporo opens, the estimated journey time from Tokyo to Sapporo will be at most 5 hours and 1 minute, but the goal is for it to be below 4 hours.