The shoe fits loosely (double up the socks or you'll get blisters). I went for two 4-mile runs and my ankles, hips and back were killing me the next day; 44 years old so I FEEL the pain more readily. I won't run again in them, but they're good to just throw on and go outside on any surface. Extremely lite and airflow is a plus! I'd imagine they'd be great for the beach as well, which I'll be checking on an upcoming trip.