I am light weight and have laid down on this mattress next to my son and you can totally feel the springs. Just even pushing down with your hand you can feel them, just wish it had better padding. Might not bother him but we have another Seely toddler mattress that is still firm but much more comfortable that my other son sleeps on, we bought this one after we had the other one just guessing that they would be pretty much the same. They aren't!