Max Surfing 2000 Hidden surfer
At the loading screen, hold R1 + R2 + Right + Square.
Bonus surfboards
Successfully complete the game to unlock a hidden surfboard. Complete the game with the new surfboard to unlock an additional surfboard. This may be repeated to obtain a total of five bonus surfboards. This may also be done in season mode to unlock five more bonus surfboards.
The image featured at the top of this post is ©The Legend of Heroes: Trails of Cold Steel III key art.