The battle was an unqualified success for the Allied forces, resulting in a withdrawal by the Japanese to a new strategic defense line in the west of New Guinea and the abandonment of all positions in the east of the island.

It was occupied by the Japanese during their invasion of the Dutch East Indies in 1942, who planned to use it as a base for their expansion towards the Australian mandated territories of Papua and New Guinea.

[4] In early 1944, after the Huon Peninsula had been secured, the Allied South West Pacific Command determined that the area should be seized and developed into a staging post for their advance along the north coast of New Guinea into the Dutch East Indies and to the Philippines.

In response, on 8 March General Douglas MacArthur sought approval from the Joint Chiefs of Staff to bring forward the previously planned landings at Hollandia to 15 April.

MacArthur's plan was bold, as it involved making a large amphibious landing deep behind the front lines in New Guinea.

[6] The Joint Chiefs of Staff also directed the United States Pacific Fleet to assign aircraft carriers to provide air support for the landings.

[7] MacArthur met with the commander of the Pacific Fleet, Admiral Chester W. Nimitz, at Brisbane between 25 and 27 March to discuss the role of the Navy in the operation.

Adachi's decision may have been motivated by a belief that Hansa Bay would be the target of the next Allied amphibious landing and that he could reinforce Hollandia at a later date.

[17] It proved difficult to accurately estimate the size and composition of the Japanese defenses, as attempts to infiltrate reconnaissance parties in the area failed.

During the early stages of the planning process MacArthur's headquarters believed that two Japanese infantry regiments may have been in the Hollandia area, but this was later discounted.

[20] I Corps under Lieutenant General Robert Eichelberger provided most of the ground forces for the combined Operations Reckless and Persecution.

[37] The Allies conducted a deception operation to ensure that the Japanese continued to believe that they would land at Hansa Bay rather than Hollandia.

[38] In response to a request from the head of the US Navy, Admiral Ernest King, the Eastern Fleet conducted a raid on Japanese positions on the island of Sabang in the Indian Ocean ahead of the landings at Hollandia and Aitape.

This attack, which was designated Operation Cockpit, aimed to prevent the Japanese from transferring air units stationed near Singapore to New Guinea.

[39] This operation had no effect on the Japanese, as the air units were being held in reserve for a planned major attack on American naval forces in the Central Pacific.

After taking evasive routes to the west of the Admiralty Islands to avoid air attack,[42] the convoy turned back towards their objective late in the afternoon.

The convoy split around 80 miles (130 km) offshore, with the Eastern Attack Group, consisting of troops assigned to Operation Persecution turning away for Aitape.

[43][44] Meanwhile, carrier-borne aircraft attacked targets around Wakde, Sarmi and Hollandia from 21 April, destroying at least 33 Japanese planes in the air and more on the ground.

The beach was narrow, though, and only allowed two LCMs to land at a time, while the even bigger LSTs had to remain offshore where they were cross loaded on to LVTs.

[48][49] Meanwhile, at Humboldt Bay Rear Admiral William M. Fechteler's Central Attack Group carrying the U.S. 41st Division also achieved complete surprise, coming ashore at two beaches: White 1, about 2.5 miles (4.0 km) south of Hollandia, and White 2 on a narrow sandspit near Cape Tjeweri at the entrance to Jautefa Bay, and about 4 miles (6.4 km) from Lake Sentani.

This bombardment was augmented with air strikes from carrier-borne aircraft, while two destroyer-minesweepers, Long and Hogan, swept the bay ahead of the main landing force.

[51] Eight waves landed at White 1 after two LCIs fired rockets at the high ground overlooking the beach where several Japanese antiaircraft guns were located.

[52] Seven LSTs and the Australian transport Westralia were unloaded over the shore at White 1, landing 4,200 tonnes of combat supplies and over 300 vehicles on the first day.

On 24 April, the beach became more congested with the arrival of scheduled reinforcements and further equipment, as well as two transports and seven LSTs carrying troops, including the corps commander and his headquarters, which had been diverted from Tanahmerah Bay.

Aerial resupply brought some relief, and on 30 April a group of 12 LCTs, towed by several LSTs, arrived at Humboldt Bay.

The situation was not fully resolved until 3 May when transport aircraft began landing on an airstrip that was hastily built by an engineer aviation battalion at Tami.

Japanese forces to the west were reconfigured to form a defense line through Biak and Manokwari,[62] while the Japanese 18th Army, still in defensive positions around Wewak, to the east, were faced with a long retreat west through the jungle having been ordered to bypass Hollandia and Aitape and reinforce the 2nd Army in western New Guinea.

[65][18] In mid-July, the Japanese launched their counterattack with around 20,000 troops, resulting in heavy fighting further inland during the Battle of Driniumor River.