Castles by the Sea is a puzzly sandcastle-building game for up to 4 players. As a group of tiny folk called "shorelings," your aim is to build and populate a seaside kingdom.

Each turn, you will place blocks and meeples on the map to earn victory points. The core gameplay is similar to abstract strategy games such as Santorini, in that players must optimize three-dimensional placement on a shared grid.

Hazards are the only source of randomness in the game, and even those will depend on player choices. Each turn, you must pick your placement carefully, optimizing your score while interfering with your opponents' plans.

The game is over after a set number of turns. Few castles will remain standing after a final onslaught of hazards, but the kingdom with the most sand dollars can claim victory.