The Battle of Vella Lavella was fought from 15 August – 6 October 1943 between the Empire of Japan and the Allied forces from New Zealand and the United States at the end of the New Georgia campaign.

In September, New Zealand troops took over from the Americans, and they continued to advance across the island, hemming the small Japanese garrison along the north coast.

On 6 October, the Japanese began an evacuation operation to withdraw the remaining troops, during which the Naval Battle of Vella Lavella was fought.

The fighting on Vella Lavella took place following the Battle of Munda Point on New Georgia, which was fought in the aftermath of the Japanese evacuation from Guadalcanal as the Allies began advancing toward Rabaul under the Operation Cartwheel plan.

After the loss of the airfield at Munda Field to US forces, the Japanese had withdrawn to Kolombangara, where they established a 10,000 to 12,000-strong garrison under Major General Noboru Sasaki.

Initial US plans following Munda Point had envisaged an assault on Kolombangara, but the US commander, Admiral William Halsey, decided to bypass Kolombangara and land forces around Barakoma near the southeastern tip of the island of Vella Lavella instead where they were to capture the Japanese airfield and develop a naval base.

[8] In late July, a small reconnaissance party was dispatched to Vella Lavella, linking up with an Australian coastwatcher, a New Zealand missionary and several natives, to gather intelligence on Barakoma and the southeast coast.

[10] On 12 August, an advanced party, consisting of naval and military personnel and a small group of troops from the 103rd Infantry Regiment, was sent from Guadalcanal and Rendova Island to Barakoma aboard four torpedo boats.

En route, the boats were subjected to aerial attack which resulted in several casualties, but their crews were able to continue to their destination where they were met by a small group of natives in canoes.

[17] These consisted of two companies of the 13th Infantry Regiment, with a combined strength of 390 soldiers, and a platoon of Special Naval Landing Force troops.

[3][11] In response, four US destroyers (USS Nicholas, O'Bannon, Taylor and Chevalier) sailed from Purvis Bay under the command of Captain Thomas J. Ryan to disrupt the Japanese landing.

While this fighting was taking place at sea, the troop-laden Japanese barges made for the north coast, where they camouflaged themselves and hid.

[3] While the main action occurred at sea and in the air, US troops ashore worked to improve the defenses around the beachhead and began limited patrol operations.

In late August, a US reconnaissance patrol searching for a suitable location for a radar site discovered a strong concentration of Japanese troops around Kokolope Bay.

McClure subsequently began an advance along the east coast of the island supported by native guides and a small group of Fijian scouts, aimed at capturing Kokolope Bay in order to establish the radar site.

Over the course of ten days, the New Zealanders fought a series of minor actions as the 35th Infantry Battalion advanced up the western coast and the 37th moved up the east.

Progress was slow, and initially combat was confined to skirmishes against small groups of Japanese hiding in well concealed jungle positions.

They subsequently had to borrow some of the craft allocated to the 35th Battalion, and supplemented these with a barge that was captured from the Japanese when a patrol boarded a vessel that had pulled into Tambana Bay.

A large scale attack was planned on the Japanese around Marziana Point and that night a heavy barrage was dialled in on the position.

A large naval battle subsequently took place north of Vella Lavella, as a group of six US destroyers engaged Ijuin's covering force.

[32] There, they joined many of the roughly 12,000 Japanese troops that had been withdrawn from Kolombangara; they would subsequently take part in the fighting on the island against Allied forces from late 1943 to 1945.

[33] Casualties during the fighting around Vella Lavella during this phase of the campaign amounted to 150 US and New Zealand naval and military personnel killed.

The 4,000-by-200-foot (1,219 by 61 m) airstrip was surveyed and cleared during August, followed by the construction of the signal tower, operations room, avgas storage tanks and an accommodation camp for personnel in September.