The following are known Action Replay Codes for Kingdom Hearts: Chain of Memories 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
f243bdd6
d8b1d250
3c27cda4
92b4ea91

Infinite Health in Battle
a68179bf
2d550dc1
6ea0d147
4af41694
c198aaf6
06e11d84
1a40afc6
9ab37e75
1e27d83b
bbfb6923

Max Health
199bb16f
a5daeb34
16f7fcb6
54d790e3

Max CP
b5ad5af0
638d72af

Super Max CP
b4207291
c57df26e

Max Moogle Points
2d96a414
88b73093

Have All Moves
5e955266
876c52b9
0c7c5e47
aae8cef6

Journal Complete
27d664ba
e5c2158a
d3551afc
69d558c4

Have All Map Cards
78941aa5
35ed5832

Have All Battle Cards
6e7b68d8
92051742
0db6a711
ebc26cc9
802e43ee
10928e11
89ae364a
bc816b98
d052c797
e0af554a
9e6eac2f
91bc8fdd
0a622869
3c462a7f
6599fa84
10585262