In the first, second and sixth SoulCalibur games, the classic numeric input for Ivy's notoriously difficult Summon Suffering throw is 376231A+G (Attack + Guard). This number combination actually holds significance as it appears to be a reference to the phone number for Namco's headquarters from before they were acquired by Bandai, being 03-3756-2311.

Allegedly, the developers used the phone number as the basis for the input as a reaction to an in-joke among Tekken and Soul Edge arcade communities, who would react to degenerate or weird stuff in the games with "gonna call Namco about this". The joke being: "If you can't do the throw, go call Namco about it." However, since this input was brought back in SoulCalibur VI long after the phone number stopped being used by Bandai Namco, this adds an additional (albeit probably unintended) layer to the joke: "Go call Namco about it. Oh wait, you can't."

It is possible to pull up both Link's and Spawn's character profiles in the PlayStation 2 version of the game via mods or hacking, despite neither character appearing in this version of the game.

There's data within the game's files for two unused characters, Wovama and Q.Takagi. When hacked into the game, both characters use Cassandra's model and will randomly pick a weapon and moveset. While the model and movesets for both character's were never created, their names do appear on the verses screen. But when used in game, Wovama's name remains blank under her health meter, and Q.Takagi's name will change to Spawn. Because neither character have models, it is speculated that they were cut very early in the game's development.

In a episode of the 8-4 Play podcast, localization producer Nao Higo confirmed that Cloud Strife from Final Fantasy VII was going to be the guest character of the Playstation 2 port. However, the deal got canned at the last minute, and Heihachi from Tekken replaced him in the end.

Each of the characters that didn't appear in the arcade release of the game are paired up against one of the four newcomers for their destined battle.

* Heihachi/Spawn/Link are paired against Raphael
* Necrid is paired against Talim
* Sophitia is paired against Cassandra
* Seong Mi-na is paired against Yun-seong

The rest are mutual battles between arcade version characters.

Soul Calibur II was the first game in the series to be a sponsor of a wrestling event, WWE Unforgiven 2003.