VOEA Ngahau Koula (P301) is a Guardian-class patrol vessel designed and built for the Tonga Maritime Force by Australia.

[1][2] After the United Nations Convention on the Law of the Sea established that all maritime nations were entitled to exercise control over a 200-kilometre (120 mi) exclusive economic zone, Australia agreed to give small patrol boats to Tonga and eleven other neighbours in the Pacific Islands Forum.

[8] 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.

[9] King Tupou VI's 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.

11 ships from 10 countries participated in the review in Nuku’alofa including Australia's HMAS Choules, China's Zibo, Japan's JS Noshiro, New Zealand's HMNZS Manawanui, UK's HMS Tamar, and the US' USCGC Harriet Lane.