Seiko Iwaido (岩井堂聖子, Iwaido Seikō, born February 23, 1984) is a Japanese actress, she was formerly known by the stage name Mai Takahashi (高橋 真唯), Iwaido made her acting debut in 2004, playing the role of Amano Sora in TV Asahi's Sky High 2. In 2005, she made her film debut as Fumie Hayashida in Simsons.

Since her debut Takahashi has worked with many prominent directors; playing Kawahime, the River Princess, in Takashi Miike's horror-fantasy children's film Yokai Daisenso (released in the U.S. in 2006 as The Great Yokai War.