Very comfortable. Not quite my style, so I returned, but I understand the craze for CROCS. The foot bed is firm but flexible with nubs that massage the sole (ooo-that's a pun!). The straps are flexible and hold the shoe well. My heel came right to the edge of the size 8M (UK: 38-39) but that's fine. I need a wide toe box but not wide shoes, and these were perfect. Very comfortable; highly recommended.