The parasailing takes place on the Banderas Bay, as it's known for its calm seas, which is ideal for such an activity.
You can book parasailing through some local tour companies, but it really isn't necessary. As you stroll down Los Muertos beach, you will see many independent operators that offer parasailing adventures. All of the providers average around $40 ($500 pesos) per session but be prepared to haggle with these guys. The plus side is that there is no need to reserve a spot. However, if you prefer to plan in . . .
