Beaufort sat on the northern bank of the Padas River, hemmed in by jungle-covered hills on three sides. Its value was not in size but in geometry: two railway lines met here, including the light railway connecting the port of Weston with Jesselton, the colonial capital now known as Kota Kinabalu. Under Japanese occupation, the town served as a communications hub for forces across the region. When Australian troops of the 24th Brigade landed at Weston on 16 June as part of Operation Oboe Six, they found no opposition on the coast. But the road inland did not exist. The only way to reach Beaufort was to follow the single-track railway through the jungle, and the Japanese had every intention of holding the town to cover their withdrawal eastward.

The advance on Beaufort required two Australian battalions to converge from different directions through appalling conditions. The 2/32nd Battalion pushed along the railway from Weston, while the 2/43rd landed at Mempakul under artillery cover from Labuan, secured the Klias Peninsula, then moved by barge along the Klias River before marching overland to the Padas. The two forces linked up at Kandu on 23 June. Between 800 and 1,000 Japanese defenders held Beaufort with forward positions covering the approaches along both the river and the rail line. The Australians pushed fourteen 25-pounder field guns forward through terrain that turned torrential rain into knee-deep mud, setting the stage for an assault that would begin at two o'clock on the afternoon of 27 June.

The artillery held its fire until the 2/43rd's infantry assault began, hoping to preserve the element of surprise. By nightfall, the Australians had fought their way into the town. What followed was a night of savage counterattacks. The Japanese launched six separate assaults, some of which devolved into hand-to-hand combat in the darkness. One Australian company became isolated, and the next morning another was dispatched to fight through Japanese positions and relieve them. Engineers worked to clear a path for tanks that had been landed from the river, though the fighting ended before armor could be brought to bear. Heavy artillery and mortar fire hammered the Japanese throughout 28 June, and by evening they began withdrawing. At least 81 were killed in ambush positions the Australians had set along their expected retreat route.

By 29 June, Beaufort was in Australian hands. The cost: seven Australians killed and 38 wounded, against at least 93 Japanese dead and two captured. Private Starcevich of the 2/43rd received the Victoria Cross for his courage under fire. The battle marked the last significant engagement in North Borneo; only minor clashes followed in the months before Japan's surrender in August 1945. With the town secured, the Australians reopened the Weston-Beaufort railway. In a detail that captures the improvised spirit of the campaign, they pressed carriages pulled by jeeps into service as rolling stock to move supplies forward, supplementing them with a steam engine in early July. The units that fought between 17 and 30 June 1945 were awarded the battle honour 'Beaufort,' a small word for a hard-won victory at the far edge of the Pacific War.