Palau and the United States are co-hosting the conference which was seen as a key global event for countries, civil society, and industry to commit to concrete and significant actions to protect the ocean.
This is the seventh year of the conference and the first time it's been held in the Pacific region.
Security around the venue was tight with roads around the conference site closed.
The conference was opened by Palau's president Surangel Whipps Jr and the US Special Presidential Envoy for Climate John Kerry.
Earlier, Kerry declared the US Embassy in Palau as the first net zero United States mission in the world.
Kerry and Whipps Jr and unveiled the new solar array which will provide 100 percent of the embassy's power needs.
During the ceremony, Kerry mentioned the latest IPCC climate report and what scientists have said.
"The world is being warned by scientists that are telling us that it is a matter of mathematic, physics not ideology not politics but the facts are telling us what is happening to our planet. 90 percent of the heating of the planet goes into the ocean," he said.
Aotearoa's commitment
The New Zealand government is committing US$3 million towards climate change assessment.
The Minister for Pacific Peoples and Associate Minister of Foreign Affairs, Aupito William Sio, made the announcement at the conference.
He said the funds would go to the University of the South Pacific and the University of Canterbury.
Aupito said the framework for the fund is still being worked through.
