Santorini: The Riddle of the Sphinx is a co-operative expansion for Santorini that adapts the competitive experience into an ongoing adventure that players navigate together.

In this expansion comprised of a series of scenarios called "riddles", players will seek to complete tactical objectives to solve the riddles. However, if players exhaust their supply of Santorini tower pieces before an objective is completed, the riddle remains unsolved and must be played again.

Each successfully solved riddle allows players to progress on the adventure map and unlock new gods to add into future riddles.