Free Triple Diamond slot game. Triple Diamond slot is a real money slot machine game by USA casino that you can practice play for absolutely free without. Triple Diamond is a classic slot from IGT and is a 3 reel slot machine with 9 paylines. Play free online!. Play the Triple Diamond slot machine for free online. This classic casino game can also be played for real money at several reputable casinos. In that section, you will find a list of the best online casinos offering three reel games like Triple Diamond. So, we hope you enjoy this game as much as you would have enjoyed Triple Diamond. CASINO OF THE YEAR All the casinos listed have an excellent range of classic three-reel games to enjoy, for free or real money. We have a feeling that you will be luckier than us.