A Sand Castle increases Sanity when standing nearby, however it only lasts a single Day, so it is best to place it when the player will be near it for a significant period of time. When the day is over and the Sand Castle decays, it will drop 1 Sand, 1 Seashell and 1 Palm Leaf. It cannot be set on fire or destroyed with a Hammer.
Sand Castles can only be placed on Sandy Turf, but much like other replaceable plants the turf can be removed and the Sand Castle will still stand. The player can then place down different turf as they please and the Sand Castle will remain.