The following are known Action Replay Codes for Rocket Power: Dream Scheme on Nintendo Game Boy Advance (GBA).
These codes were also known as GameShark Codes and in most cases will work on both devices.

These codes are for the U.S. version of the game.

Master Code – Must Be On
41007dff
36417fcb
7b81934c
1986550c

Max Stars
bf6e3505
e0b6b5dc

Infinite ZZ
8ece2a25
92bbc865

Have All Items
965ed41d
b1fc267d

1st Story Levels Complete
e6fb254b
770ec21b
48819ea9
ce5ee2a8
8d5a1e1d
24cc5b8c
599098ad
404a927c
1c9ad85f
27c68549
33cde9b6
8eeea6e7

Unlock Reggie
8ee52f50
43981a1b

Unlock Sam
f4e36549
c40a93da

Unlock Twister
248c1da0
4d51600b