Very comfortable, it is not needed to have any kind of "adaptation" period because they are soft and don't hurt my feet. Straight from the beginning I used them every day for 2 weeks on vacation and I was very satisfied and happy with them. I have ordered size 38 which is the same of for the other barefoots (I used to wear 39 of the other non-barefoot shoes and sandals). There is only one small thing - since the sole is so flexible, sometimes if I didn't do a good step, it would flip and I would step on it, so you just have to make sure to do proper steps.