In Mahjong on the Beach the player controls a young man in a large coastal city, who meets various scantily clad young women and plays mahjong with them. The player character can be navigated on a top-down map, accessing locations that lead to semi-random encounters with girls and subsequent mahjong games. Winning these games unlocks new locations and allows purchase of items that can be used during the encounters to the player's advantage. In the versus mode the player can directly compete against any of the girls; however, this mode contains only mahjong matches themselves, without any graphical indication as to which opponent the player character is facing.