All the best online gambling websites offer bonuses, because it keeps existing customers interested, and it encourages new customers to sign up with them. Underdog Fantasy US also offers a welcome bonus, and in this review, just as we do with all our other online gambling reviews of operators, we’ve taken a  look at it. You’ll find out what the bonus is, how to unlock it, and how long you have to use it! Check out our Underdog Fantasy US reviews to find out more!