Is it possible to mix certified and uncertified divers?

An uncertified diver needs to have a PADI Instructor dedicated just to him/her and cannot dive more than 12 meters, which is the maximum depth during a discover scuba diving course, according to the PADI internationally recognised standards. On the contrary, certified divers will dive in groups (maximum 4 divers is recommended) with a PADI Divemaster guide and between 18 to 31 meters of depth.