Unlike the PJ Masks, the PJ Babies behave like babies, especially bad behaved ones when Motsuki told them (along with Baby Luna and Baby Romeo) to be bad. In the end, PJ Robot told all five babies to be nice and even convinced Motsuki to do the same thing. In "Terrible Two-Some", Kitten Boy also acted like a kitten as he ran, walked, and pounced like one, but then walked and ran on two legs like a real person.
The PJ Babies have the same powers as the PJ Masks, but they only use one of their powers instead of their other powers since they do not know how to use them like the PJ Masks.
Kitten Boy: Like Catboy, Kitten Boy has super cat speed. But while he said "Supa cat speed! And whoosh!" in "Terrible Two-Some," he said "Supa dupa speedy cat!" in "Big Sister Motsuki."
Chicklette: Like Owlette, Chicklette can use Super Owl Wing Wind, and when using it, she says "Supa owly wingie wind!"
Baby Gekko: Like Gekko, he has Super Gekko Muscles, and when he activates his power, he exclaims "Muscle wuscles!"
The PJ Babies appear to be the same as the PJ Masks, but unlike them, they have big cute eyes and talk in adorable baby voices.
Kitten Boy and Chicklette are known as Le Petit Chat (lit: The Little Cat) and Minibou (lit: Mini-Owl) in the French dub of the show.
Unlike Baby Luna and Baby Romeo, who giggled after being zapped by the Baby Beam, the PJ Babies cried after being zapped instead, similar to how Robot did when he got zapped by the baby beam by accident in "Terrible Two-Some".
While Kitten Boy and Chicklette had to learn how to use their powers by Gekko in "Terrible Two-Some", Baby Gekko is the only baby of the PJ Babies who already knows how to use his powers mainly due to Motsuki telling him to be mean.