The Prison Guards were the robots tasked with guarding the Prison Planet. They were seen several times with the Prison Warden while he visited Ratchet's cell. The Prison Guards act under the Warden's command, and aided him in making Ratchet's stay on the Prison Planet "less than hospitable." The Prison Guards were also seen releasing Ratchet after Klunk's defeat. Despite the riot that took place during the events of Secret Agent Clank, they played no role on the efforts to prevent the criminals from escaping.
- The Prison Guards appear to be unarmed, which is odd, considering that they guard an intergalactic high security prison.
- The Prison Guards did not speak during the events of Secret Agent Clank.
- Secret Agent Clank (first appearance)