Jacqui Evans won the Goldman Environmental Prize after leading a five-year campaign to better protect Cook Islands waters.
Her work led to the Marae Moana Act which established marine protected areas and banned large-scale commercial fishing and seabed mining within 50 nautical miles of the 15 Cook Islands.
Jacqui Evans said she wanted to leave children in the Cook Islands with a clean ocean so that they are able to eat fish from the sea into the future.
"I don't want to leave them with a mess. It's been heartbreaking to see families not be able to get the amount of fish they have been used to getting," Jacqui Evans said.
Jacqueline Evans was one of of six recipients of this year's Goldman Prize, which also included environmentalists from Chile, the US, North Macedonia, Liberia and Mongolia.
The Goldman Environmental Prize recognises "grassroots" leaders who are involved in local efforts to create positive environmental change through community or citizen participation in issues that affect them.
Recipients of the prize are selected by an international jury from nominations submitted by a global group of environmental organisations and individuals.