In spite of the losses sustained during the air raid, Japanese forces successfully occupied Lae and Salamaua and began the construction of a base and airfield.

In early 1942, the Japanese high command began planning operations in the New Guinea and the Solomon Islands, as part of an overall strategy of establishing bases in the South Pacific from which to interdict Allied lines of communication between the US and Australia.

[2] To support the operation, the Imperial Japanese Navy formed an escort group under the command of Rear Admiral Kajioka Sadamichi.

The Horie Unit was assigned the task of capturing Salamaua, including the airfield and township, while the naval landing force was given the responsibility for taking Lae.

[7] A small detachment of the New Guinea Volunteer Rifles and some men from the 2/22nd Infantry Battalion set about the demolition of key infrastructure around Salamaua, and after a minor skirmish which resulted in one Japanese casualty, they destroyed the bridge over the Francisco River and then withdrew into the hills towards Mubo.

The Task Force, under the command of Admiral Wilson Brown, had avoided detection by the Japanese, and the approach of their aircraft from over the Owen Stanley Range enabled the attackers to appear seemingly out of nowhere.

The 201 km (120 mi) distance from which the planes were launched provided security for the task force and helped ensure surprise against the Japanese.

[10] Approaching the northern landing areas, the attack commenced with the SBD Dauntless dive bombers of Lexington's Scouting Squadron 2 (VS-2), which struck the Japanese shipping at Lae at 09:22.

[11] Following the carrier aircraft strike, eight B-17 bombers of the 435th Bombardment Squadron flying from Garbutt Field at Townsville arrived and bombed the target area as well, causing further damage.

[18] While Japanese plans to secure Port Moresby were postponed after the Battle of the Coral Sea,[19] they continued operations in the vicinity, and developed an airfield and large base facilities in the Salamaua–Lae area.