The following are known Action Replay Codes for ICO on Sony Playstation 2 (PS2). These codes were also known as GameShark Codes and in most cases will work on both devices.

Device Compatibility: Action Replay & GameShark (Version 1 & 2)

Master Code – Must Be On
EC87A648 143ACAF4

Save Anywhere: Press L2
0CBF92F6 1456B10C
4CF6B274 1456E7AE

Dead Enemy AI
1C818848 15F6E79D
1C81884C 1456E7A5
1C8A3C70 15F6E79D
1C8A3C74 1456E7A5

Walk On Air: Press Select
DC938022 142ED6F7
1C899850 15F6E79D
1C899854 1456E7A5

Norm.Walk: Press Select+X
DC934022 142ED6F7
1C899850 39A1B095
1C899854 91D38BAD