There are 13 worlds in the original Kingdom Hearts.
That total counts the game’s distinct story locations, including Sora’s home, Destiny Islands; the refuge of Traverse Town; Disney-based worlds such as Wonderland, Deep Jungle, Agrabah, Atlantica, Halloween Town, and Neverland; and major original locations including Hollow Bastion and the End of the World.
The count can cause confusion because some locations function differently. The Hundred Acre Wood is an optional world accessed through pages in Merlin’s book, while Traverse Town serves mainly as a hub. The End of the World is also unusual because it is formed from the remains of worlds consumed by the Heartless.
Players may also see different totals in discussions that include cutscene-only locations, later releases, or worlds from sequels. For the original Kingdom Hearts game’s conventional playable-world count, 13 is the standard answer.