Diaper Recommendation

Hey ladies, I need some help. My 18mo boy sleeps 12-13hrs a night (I know we're lucky)..but when he wakes up he's either drenched or slightly wet from pee. I feel really bad cause he sleeps in it...we've tried overnight diapers..but not all seem to work. He's not ready to be potty trained yet ( can't wait for the day)

Any recommendations!!

Thank you :)