The following are known Action Replay Codes for Lemmings 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

Stop Timer
013208c9

Infinite Climber
0163f8c8

Infinite Floater
0163f9c8

Infinite Bomber
0163fac8

Infinite Blocker
0163fbc8

Infinite Builder
0163fcc8

Infinite Basher
0163fdc8

Infinite Miner
0163fec8

Infinite Digger
0163ffc8