The "high islands" such as Tahiti, Moorea, Tahaa/Raiatea and Bora Bora are of volcanic origin and more recent than the atolls.

The barrier reef supports small islets (motu) and is cut through by channels (passes) originally created by the fresh water descending from the mountains where the coral could not grow.

These islands have a larger continental shelf than the atolls and some species are more frequently encountered than in the Tuamotus.

When planning a dive holiday, it is unconceivable to experience only one of these archipelagos when their individual scenery and species are so complimentary.