The Kuroshio (くろしお) is a limited express train service in Japan connecting Kyoto, Shin-Osaka, Tennōji, Wakayama, Kii-Tanabe, Shirahama, and Shingu via the Tokaido Main Line, Osaka Loop Line, Hanwa Line, and Kisei Line, operated by West Japan Railway Company. This article also covers the derivative limited express trains, "Super Kuroshio (スーパーくろしお)" and "Ocean Arrow (オーシャンアロー)", the names of which were discontinued from start of the revised timetable on 17 March 2012.

The Tōkaidō Main Line is a major Japanese railway line of the Japan Railways Group network, connecting Tokyo and Kōbe stations. It is 589.5 km (366.3 mi) long, not counting its many freight feeder lines around the major cities. The high-speed Tōkaidō Shinkansen largely parallels the line.