Bought these for running because of the "seamless toe" since a seam will sometimes blister the top of my big toe. I would not say they are completely seamless--there is a little bit of extra material there--but it's just a small amount and it's very smooth. I've run in both pairs I bought, and they have been very comfortable. Went by the size chart and got larges for my size 11.5/45-46 feet, and they are just large enough, partially because they are so stretchy. I hang them to dry rather than using the dryer, which should keep them from becoming too small. They seem to be of very good quality and I hope they will last.