Prince Bo (にじハムくん, Nijihamu-kun) is Prince of Rainbowland. He appears in some of the later episodes of Hamtaro. He also appears in the video games Hamtaro: Rainbow Rescue and Hamtaro: Ham-Ham Games.

Prince Bo can make rainbows with his magic umbrella. The Rainbow Girls have a crush on him. Prince Bo can also fly with his wings, which resemble a ladybug's. His name is probably a play on the word Rainbow; (Rain"Bo"w).