no...a 3 yr old is too young to sit in a "booster" like seat with a normal seat belt....risk if it you want but even my 2 yr old can undo a normal seatbelt as we had to sit her on a booster seat for one journey within 5 mins she had it undone....just as well the galaxy is so big that i could climb over and sort her out! you want a 5 point belt for the child. you know how wriggly a 2/3 yr old can be when they have had enough of sitting down.least in a 5 point one you know she is going to stay there.