I only use waterproof shoes and boots and have never had an issue with sweat. And I sweat like a pig. But I also don't live where it gets crazy hot. If you think it might be an issue, they make a Moab Vent that might work for you. Crazy sale on Amazon if your size is available. https://www.amazon.com/Merrell-Mens-Moab-Hiking-Walnut/dp/B01HFPP1ME/ref=asc\_df\_B01HFPP1ME/