ESA Open Water course has been conceived to introduce all the concerned people and in good psychophysical state to recreational dive activities, in the greatest respect of safety. The course is divided into two main parts with which to obtain the ESA New Diver and Open Water Diver Certifications. The purpose of the ESA Open Water Diver course is to enable people to dive, according to the Certification obtained, in places with the same conditions as during the instructive phase, with a certified diver and keeping within the non-decompression limits. ESA Junior and New Diver programs indeed provide that, after having obtained the respective Certification, the diver go along with an ESA Professional diver. The approach must be as friendly as possible and highlight all the aspects linked to the diver safety as well as the environment knowledge and respect, without neglecting the participants’ amusement. During the program the student will be able to learn the essential elements to dive safely and to learn and practice the dive techniques in order to make easier and as safety as possible the exploring of the underwater world keeping within the fixed limits.