Treasure Chests are scattered throughout the worlds of the Kingdom Hearts series. Finding treasure chests is the primary method of obtaining items within the Kingdom Hearts series. Chests are usually out in the open, though they can sometimes be hidden, requiring interaction with the environment or the use of a Trinity to reveal.
In Kingdom Hearts: Chain of Memories and Kingdom Hearts Re:Chain of Memories, treasure chests are only available using either Calm Bounty, Guarded Trove, False Bounty, or Key to Rewards cards (except for a single, naturally appearing chest in the 100 Acre Wood), while no chests appear at all in Atlantica in Kingdom Hearts II, or in Kingdom Hearts coded and Kingdom Hearts Re:coded, as they are replaced by Prize Blox.
In Kingdom Hearts and Kingdom Hearts: Chain of Memories, chests have three main designs, which have slightly different designs based on the world they appear in. Green, red, and blue chests appear indiscriminately throughout Kingdom Hearts, while in Kingdom Hearts: Chain of Memories, red chests are used for Bounties and the first set of Room of Rewards Bonuses, and blue chests are used for the Kingdom Hearts Re:Chain of Memories-exclusive second set of Bonuses.
Along with the more common types of treasure chests, the world of Atlantica in Kingdom Hearts contains a large, sunken treasure chest, as well as four types of giant clam shells that operate similar to chests. The clam shells come in four different types: "Physical", "Fire", "Blizzard", and "Thunder", specifying the attack attribute that must be performed to open them, and are distinguished by their hue.
In Kingdom Hearts II, Kingdom Hearts 358/2 Days, Kingdom Hearts Birth by Sleep, and Kingdom Hearts 3D: Dream Drop Distance, chests come in small and large sizes, and vary based on the world they appear in. The two sizes of chest for a specific world have similar designs, although there are always slight differences, and the designs for each size and world are constant between the four games.
In these games, the size of a chest determines its contents. Small chests can contain items, synthesis materials, accessories, or non-Keyblade weapons in Kingdom Hearts II, commands or crystals in Birth by Sleep, and item commands, Dream Pieces, or Training Toys in Dream Drop Distance. Meanwhile, large chests can contain maps, Keychains, or key items in Kingdom Hearts II, panels, synthesis materials, or Slot Releasers in 358/2 Days, maps, recipes, or pieces of Xehanort's Report in Birth by Sleep, and Spirit Recipes or various combat commands in Dream Drop Distance.
The small chests of the Realm of Darkness and Land of Departure share the same design with the standard chest but are colored slightly different. The Spiderchest Unversed mimic large chests, although they do not replicate the designs exactly.
In Kingdom Hearts χ, only small chests appear, using the design of the small chest from Kingdom Hearts II.