(or equivalent certification from another organisation) (baliocean.com)
Diving is done with a comfortable ratio of 4 divers to 1 Divemaster, and all groups are structured in such a way that divers with equivalent certification and / or experience dive together. (idcthailand.net)
Emperor requires that you have a minimum of 30 logged dives and Advanced Open Water or equivalent certification for all Indonesian diving itineraries. (scubatravel.com)