When, in the natural environment, the submerged group is led by a supervisor, that supervisor must hold a qualification mentioned in Annex III-15 b. This person is responsible for the conduct of the dive and ensures that its characteristics are appropriate to the circumstances and the abilities of the divers.
When at least one of the supervised divers or the person supervising the group uses a mixture other than air, the latter must also demonstrate the skills corresponding to the mixtures used in accordance with Annexes III-17 b, III-17 c, III-18 b and III-18 c.