BetDSI Mobile App, Live, Sports Betting, Racebook and Bonuses Last Updated on 2 weeks ago BetDSI Bookmaker History And License BetDSI is owned by Diamond Sportsbook International, an established company out of Costa Rica. They run safe and legal online gambling sites. BetDSI is mainly known for its sportsbook, but they also offer casino games, horse racing, and even online poker. In 2017, BetDSI separated from longtime partner BookMaker. Though there was some concern about shifting everything in-house and running an independent operation, but the transition has been fairly seamless.