Kingdom Hearts - III, II.8, Unchained χ & Union χ (Cross) - Original Soundtrack

The Kingdom Hearts - III, II.8, Unchained χ & Union χ [Cross] - Original Soundtrack was released in Japan on November 11, 2020. The 8-CD set contains all of the songs from Kingdom Hearts III, Kingdom Hearts III Re Mind, Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-, Kingdom Hearts χ, Kingdom Hearts χ Back Cover, Kingdom Hearts Unchained χ, and Kingdom Hearts Union χ [Cross] for a total of 161 songs. Customers who pre-order the soundtrack will receive a bonus ninth disc featuring two brand new arrangements from Kingdom Hearts Melody of Memory.

This collection is available in North America as a digital release and sold on music platforms, such as Apple and Amazon Music, which contains most of the songs from the 8 discs in a single collection. The differences are that the English version of "Let It Go" and "Simple and Clean (Ray of Hope Mix)" are added to the International release (placed after their Japanese counterparts in the track listing) in place of "Face My Fears (Japanese version)" and "Chikai" due to copyright reasons.