VOEA Ngahau Koula (P301) is a designed and built for the Tonga Maritime Force by Australia. After the United Nations Convention on the Law of the Sea established that all maritime nations were entitled to exercise control over a exclusive economic zone, Australia agreed to give small patrol boats to Tonga and eleven other neighbours in the Pacific Islands Forum.
Tonga was given three s in 1989, 1990 and 1991, , and . Those vessels were designed to have a working life of at least 30 years, so Australia designed the Guardian class, a slightly larger, and more capable replacement class. Australia delivered Ngahau Koula to Tonga on June 21, 2019. A second replacement vessel will follow in 2021.
The vessel's name means "Golden Arrow". She has been designed to be able to accommodate crews of mixed gender.
Operation career Nahagau Koula was commissioned by King Tupou VI on October 16, 2019.
The vessel was involved in the response to the 2022 Hunga Tonga–Hunga Ha'apai eruption and tsunami, evacuating all residents of Mango island to Tongatapu.
King Tupou VI sailed aboard Nahagau Koula as his official vessel during an international fleet review in honor of his 65th birthday and 50th anniversary of the Royal Tongan Navy on 4 July 2024. Eleven ships from ten countries participated in the review at Nuku’alofa including Australia's , China's Zibo, Japan's , New Zealand's , the United Kingdom's , and the American .
On 4 September 2025, Ngahau Koula participated in the mobile Fleet Review in the event of the 50th Independence Day of Papua New Guinea. The review was held at the Port Moresby harbour and was conducted and led by . A total of seven warships from five nations took part in the review formation, with the other ships being the , HMPNGS Gilbert Toropo, , and . Each ship sailed at an interval of with precision.
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