Great booties! they keep my feet nice and comfy on those colder days. I have heard people say that if you are a half size you should go down but i would NOT recommend that with these. they seem to run fairly small already and the boot does loosen up a bit once they get wet but only the neoprene does, not the rubber sole, that bad boy stays true to size! i wear a 10.5 and the 10 crushed my toes and the 11 fits nice.