Motoka Arai

is a Japanese retired sprinter. She competed in the 4 × 100 metres relay at the 1997 World Championships, the 100 metres and 4 × 100 metres relay at the 1999 World Championships and the 4 × 100 metres relay at the 2003 World Championships. She was a seven-time national champion in the 100 metres and a six-time national champion in the 200 metres at the Japanese Championships. She is the former Japanese record holder in the 100 metres and 200 metres, and the current Japanese record holder in the indoor 200 metres.

She married Japanese sprinter Shigeyuki Kojima in February 2004. She changed her name to Motoka Kojima, but she reverted to her original name.

Personal bests

International competition

National titles Japanese Championships 100 m: 1998, 1999, 2000, 2001, 2002, 2003, 2004 200 m: 1998, 1999, 2000, 2001, 2002, 2003