The casino only appears to open when the ship is out to sea. Like, as soon as the ship sets sail, the casino opens. Although I've been up late, I can't tell you how long it stays open. For all I know, it stays open until docking at the next port. The only port that I'm aware the casino was ever open while in port was Aruba, when it opened at 7PM. The ship was in port all day, but it did not open untill then and I was surprised it opened then, since the ship didn't sail until 11PM.