The following are known Action Replay Codes for Legend of the River King 2 on Nintendo Game Boy / Color (GB / GBC). These codes were also known as GameShark Codes and in most cases will work on both devices.

Device Compatibility: Action Replay & GameShark

Have Hook (M)
910992cf

Max HP
91e75ecf
91035fcf

Infinite HP
91e760cf
910361cf

Infinite Gold
910f64cf
912765cf

Max EX
91ff66cf

Hour Modifier
91xx0ed0
Replace xx with 00 – 0c

Minute Modifier
91xx0fd0
Replace xx with 00 – 3c

Have Lug Worm
910989cf

Have Frog
910988cf

Have Marine Worm
91098acf

Have Mussel
91098bcf

Have Krill
91098ccf

Have Rock Crab
91098dcf

Have H. Mackerel
91098ecf

Have H.M. Fillet
91098fcf

Have Mackerel
910990cf

Have Fingerling
910987cf

Have Paste Bait
910986cf

Have May Fly Larvae
910985cf

Have Mosquito Larvae
910984cf

Have Insect
910983cf

Have Maggot
910982cf

Have Earth Worm
910981cf

Have Hook (S)
910991cf

Have Hook (L)
910993cf