Idaho has set its legal gambling age at 18.Georgia has set its legal gambling age at 18 (gambling is only legal on cruise ships).The gambling age by state for casinos and legal gambling establishments are listed below. Are you a gambler or do you have ambitions of becoming a professional gambler? Maybe you just like to hit the casino for some fun with friends? Either way, and for whatever reason, you want to gamble or visit the casino, it is important to make sure you are of age to do so first.