Is FanDuel Legal? FanDuel Strategy Course 101 Playing FanDuel Daily Fantasy Contests – Legal or Illegal? Fantasy sports leagues have been around for quite a few years now. There is a difference between the traditional season-long leagues and daily fantasy sports (DFS). However, the DFS concept has exploded in popularity over the last few years. One of the primary DFS sites is FanDuel. Almost immediately, there were questions surrounding the legality of the idea.