Perfect for my 9 month old son. I've been looking for something he can't pull off and this certainly does the job. Thing is, his feet gets really sweaty so if he has it on for too long the outer soles get wet lol. For reference, his foot is about 5 inches long and I bought a size 18-24 and its perfect with room to grow. 12-18 might have been a snugger fit.