I applied online. The process took 1 day. I interviewed at Six Flags (Gurnee, IL) in May 2013
Interview
Easy. Went over past relevant work experiences and high school activities. Interviewer was a lead lifeguard, we were both still in high school. You don't need too much experience, just be normal. Even if you are already a lifeguard, you will have to relearn everything their way in training.