Description from the publisher:

In Small World: River World, players discover new maps full of water regions haunted by merciless pirates. Players need to defend their precious harbors against them, fight them on the river, and still keep an eye on their opponents! Some regions such as the shipyard or the temple of the seer may help them to have the upper hand, but in River World, there is still not enough room for everybody. And random events that trigger on each turn add to the chaos!

Small World: River World includes two double-sided game boards, i.e., four maps in total, one for each of the four possible player configurations.

Note: To play with this expansion, you need the following contents from Small World: race banners, special power badges, markers, victory coins, and the reinforcement die. The publisher recommends removing the "Flying" special power before using this expansion.