The 381 series is a tilting DC electric multiple unit (EMU) train type introduced in 1973 by Japanese National Railways (JNR), and currently operated by West Japan Railway Company (JR-West), and formerly also operated by Central Japan Railway Company in Japan.

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.