The Islands Region of PNG is particularly rich in marine life.  Kimbe Bay reefs feature luxuriant coral growth, with spectacular hard coral formations, masses of crinoids, and a staggering diversity of fishes, 840 identified species. By comparison, the total number of fish species found in the tropical and subtropical Western Atlantic, Gulf of Mexico, and Caribbean area numbers somewhere in the neighborhood of 500 species.  About 100 species of damselfish occur in Papua New Guinea, over six times the number present in the entire tropical and subtropical Western Atlantic Ocean, Caribbean Sea, and Gulf of Mexico.

In recognition of the diversity and importance of Kimbe Bay's natural environment, the Walindi Nature Centre was established.  Several local and international environmental non-government organisations are based at the Nature Centre, including Mahonia Na Dari, which conducts the only specialised marine environment education program below university level in PNG.

A complete Kimbe Bay fish list of identified species as at 2002, is attached.  This includes several species first identified in Kimbe Bay such as the wrasse, Cirthilabrus walindi, and several Gobies including Trimma rubromaculatus and Vanderhorstia flavilineata.

Over 400 reef-building coral species are found in Kimbe Bay. Large coral pinnacles and seamounts that rise to within a few meters of the surface, are characteristic. Other reef structures include atolls, large barrier reefs, patch reefs, spur-and-groove systems, and shallow shoals (with their crests within as little as less than one meter beneath the surface) where soft corals and sea fans give way to vertiginous walls, the sheerest drop-offs being found further offshore.

Spinner dolphins, killer whales, sperm whales, pilot whales, and other toothed whales are frequently seen in Kimbe Bay.  The most common shark species is the gray reef shark , followed by the placid white tip reef shark, scalloped hammerhead, silvertip, and blacktip reef shark . The very large and very placid whale shark, is also seen in Kimbe Bay.  WNB hosts five species of turtle, including the leatherback and green turtle, as well as the dugong.

This extraordinary richness of the marine environment contributes to the quality of the diving and fishing of West New Britain.