Because the first game was re-released, there was speculation whether Tetsuya Nomura would do the same with Kingdom Hearts II. In a Weekly Shōnen Jump interview with Nomura, he expressed interest in a possible international version of Kingdom Hearts II, although there were no definite plans. He said that should a "Final Mix" version arise, he had a "trump card" in mind, with such features as the Mushroom Heartless found in the first Kingdom Hearts game. In September 2006, Square Enix announced Kingdom Hearts II Final Mix, featuring new scenes and gameplay elements. Like the first re-release, this version would combine English audio with Japanese text and also use the "Sanctuary" theme song instead of "Passion". New cutscenes, however, used Japanese voice acting, as they mostly featured Organization XIII members from Kingdom Hearts: Chain of Memories who did not yet have English voice actors.
Kingdom Hearts II was re-released in Japan on March 29, 2007 as a 2-disc set titled Kingdom Hearts II Final Mix+. The first disc contains Kingdom Hearts II Final Mix with a new secret movie and additional battles and items. The second disc contains Kingdom Hearts Re:Chain of Memories, a 3D PlayStation 2 remake of Kingdom Hearts: Chain of Memories with extra scenes and voice acting. The battle system maintains the card gameplay, with the addition of Reaction Commands from Kingdom Hearts II. Like the first game's Final Mix, the two games serve as a canonical update to the series. The book Kingdom Hearts -Another Report- was included along with the game for those who reserved a copy. Based on Amazon.com figures, Final Mix+ was the number one PlayStation 2 game in sales during the week of its release in Japan. In early 2010, Nomura expressed concerns about releasing another "Final Mix" version of a Kingdom Hearts game, thinking that the reason why Kingdom Hearts II Final Mix+ was very popular was due to the addition of Kingdom Hearts Re:Chain of Memories