Oceania refers to fourteen sovereign island nations, which themselves are comprised of dozens of smaller islands. Many are not inhabited or are extremely infrequently visited by tourists. I’ve indicated which islands are covered by the Oceania Global Directory pages.
The Cook Islands are in free association with New Zealand, members of several UN specialized agencies and have been recognized “full treaty-making capacity”. Still they are neither member states nor non-member observer states.
Cook Islands is comprised of many islands but the majority of the population lives on Rarotonga.