To be honest I don't know. But you would need to b=pack the rest of the cooler really tightly with icepacks to maximise the time. If you try it let us know how you get on!
Hi, yes you could put ice in these coolers. The seams at the bottom of the bag are welded so it's waterproof - however the zip isn't waterproof. So I guess if you were keeping the bag upright and it wasn't too full and you weren't moving it around too much it would be OK. The Day Escape range from Hydro Flask are designed to take ice. These coolers are fully waterproof with a waterproof zip and the handles are more sturdy to take more weight.
