For the majority of these scenarios, the sports betting age is 18. States without state regulated betting, do not have specific laws for the legal age for online sports betting, leaving it up to the international operators that run the books. Depending on the state that bettors are located in, they have complete access to one of them, or both. There are state regulated sportsbooks and online international licensed sportsbooks that can be used throughout the United States. What Sportsbooks Offer 18 Verses 21 Sports Betting