I've never used them for hamsters, but I do use them for my hedgehogs though. As long as the top is well ventilated, and the bin itself is kept very clean so ammonia didn't build up, I'm sure they'd have enough ventilation. My biggest concern would simply be that every hamster I have ever had was a voracious chewer. They could have a hole big enough to escape from a soft plastic bin in under 10 minutes if they set their mind to it - and having smooth sides and rounded edges is not always an effective deterrent. You'd definitely have to find the right bin, and have plenty of distractions in his cage so he chooses to chew on other things instead of trying to sample the bin itself.