They are free, but DEFINITELY sign up ahead of time as the space is VERY limited!! It was kind of tricky taking step on a moving ship... LOL!! But we all did okay. I think there were 4 of us plus the instructor and I think there would have been room to comfortably fit one more person. I didn't care for the schedule though. I prefer to do my exercise first thing in the morning and only one step class could accomodate that for me. You have to go to the spa to sign up.