Seastalker is an interactive fiction game written by Stu Galley and Jim Lawrence and published by Infocom in 1984. It was released simultaneously for several popular computer platforms of the time, such as the Commodore 64, Apple II, and IBM PC compatibles (as a self-booting disk). The game was marketed as an introduction to interactive fiction for preteen players, having difficulty rating of "Junior." It was the only game to ever use this rating, which was replaced by the "Introductory" label given to games such as "Wishbringer". It is Infocom's twelfth game.