Splash about happy nappy sizing

Help i'm confused, everywhere has different sizing and i'm not sure which size to get for ds I had ordered him and xxl (toddler) but it just falls down when he walks. Not sure whether to get a large or xl

A large used to fit Tyler over a despicable swim nappy but if I bought one to go over his reusable swim nappy then I would go for an xl - Tyler is approx 25lbs and in large everything nappy wise but generally on the tightest snaps xx

I used to do Waterbabies with Connor and he had a medium from about 8 months and it now fits Finn at over 2 years! Finn is very dinky but I do think splash about nappies are on the large side. Unless your ds is a big build I'd probably go for large rather than x-large.

ETA that's when using it over a Huggies little swimmer disposable.

Nathan is about 23lbs i think and he wears a large fine

Thanks ladies think i'll go for a large. Ds is about 24/25lb but a slim build os think this one will be the better one to go for!

alister is still in a medium and 12mnths and 21lb, but its getting rather tight! so were be moving up to a large very soon!
id say try an xl