The central islands are predominantly coral cays, and those of the east are of volcanic origins.

There lies a chain of five coral cays, barely above the tide.

Hoskyn Islands is a pair of small coral cays.

A major clean-up campaign was conducted to protect the sensitive areas such as the coral cays and sand dunes.

The coral cays belong to two distinct types:

Their journey was taking them over a tapestry of shoals, atolls, coral cays, and true continental islands.

Fairfax Islands is a pair of small coral cays, both of which have been used as a bombing range.

Most of the islands are low-lying coral cays, vegetated with grass, herbs and vines.

The islands in the centre are mostly coral cays.

Collectively they comprise 241 ha of coral cays.