Swimming is a form of movement that appears in Kingdom Hearts, Kingdom Hearts Final Mix, Kingdom Hearts II, Kingdom Hearts II Final Mix, Kingdom Hearts Birth by Sleep, Kingdom Hearts Birth by Sleep Final Mix, and Kingdom Hearts 3D: Dream Drop Distance.
Surface swimming appears in Kingdom Hearts, Kingdom Hearts Birth by Sleep, Kingdom Hearts 3D: Dream Drop Distance, and Kingdom Hearts III — essentially, the character will swim around in the water in a breast-stroke style. They cannot jump, so they must get to a shore in order to get out of the water. In Kingdom Hearts Birth by Sleep, surface swimming is the only kind of swimming available, and is only used at Neverland. However, in Kingdom Hearts Birth by Sleep Final Mix, swimming is also possible in the Mirage Arena match against Monstro. In Kingdom Hearts 3D: Dream Drop Distance, surface swimming is the only kind available and is only used in both Symphony of Sorcery and Traverse Town. In Kingdom Hearts Birth by Sleep Terra, Ventus, and Aqua can swim faster by holding and in Kingdom Hearts, after he learns Mermaid Kick, Sora can swim faster by holding .
In Kingdom Hearts and Kingdom Hearts II, Sora can swim in all three-dimensions while in Merman Form at Atlantica. In Kingdom Hearts, Sora can dive with and rise with . In Kingdom Hearts II, the right stick is used to move vertically. Sora can also use to swim faster and to use Dolphin Kick.
In Kingdom Hearts III, Sora can also swim in all three-dimensions while in The Caribbean and Scala ad Caelum. He can dive underwater by pressing when surface swimming, though he can also dive by landing in the water while in Dive Mode. While underwater, he can ascend with , descend with , and swim faster with , although this time, he spins the Keyblade as a makeshift propeller. Unlike in Kingdom Hearts, most forms of offensive magic work completely differently underwater, and are given Sea designations.