i'm sure it'd be a good idea to move him to a small bed. i have a 20 month old and had recently moved him to his new toddler bed. toddler beds have side bars so he can move around and not fall off.. plus they sit pretty low, a few inches off the floor so its easy for them to climb in and out of their super big boy beds, heh... but really, if your son walks and climbs, he'll be alright..
