The Invasion of Lae-Salamaua, called Operation SR by the Japanese, was an operation by Imperial Japanese forces to occupy the Salamaua-Lae area in the Territory of New Guinea 8–13 March 1942 during the Pacific campaign of World War II. The Japanese invaded and occupied the location in order to construct an airfield and establish a base to cover and support the advance of Japanese forces into the eastern New Guinea and Coral Sea areas. The small Australian garrison in the area withdrew as the Japanese landed and did not contest the invasion.
In response to the Japanese landings, a United States Navy aircraft carrier task force including the carriers Yorktown and Lexington struck the invading Japanese naval forces with carrier aircraft on 10 March. Supporting the carrier aircraft were eight B-17 bombers of the 435th Bombardment Squadron of the 19th Bombardment Group from Garbutt Field, Townsville, Australia and eight Royal Australian Air Force Hudson bombers of No. 32 Squadron from Port Moresby, New Guinea. The raid sank three transports and damaged several other ships.
In spite of the damage sustained during the air raid, Japanese forces successfully occupied Lae and Salamaua and began the construction of a base and airfield. Air units based at the airfield later supported an air superiority campaign against Allied forces at Port Moresby. In July 1942 after the Japanese abandoned plans to invade Port Moresby from the sea, the base at Lae-Salamaua supported the ultimately unsuccessful Japanese land offensive towards Port Moresby along the Kokoda Track.
To support the operation, the Imperial Japanese Navy assigned the heavy cruisers Aoba, Kinugasa, Furutaka and Kako of Rear Admiral Goto's Cruiser Division 6, the light cruisers Tenryu and Tatsuta of Rear Admiral Marumo Kuninori's Cruiser Division 18, the destroyers Mutsuki, Mochizuki and Yoyoi of Destroyer Division 30, and Asanagi, Oite, Yūnagi of Destroyer Division 29, along with the light cruiser Yūbari of Rear Admiral Kajioka Sadamichi's Destroyer Squadron 6, fueled by the fleet oiler Tōhō Maru.
The invasion fleet left Rabaul on 5 March 1942, escorted by the four heavy cruisers, two light cruisers, eight destroyers and assorted auxiliary vessels. The troop transports Yokohama Maru and China Maru sailed for Salamaua, while the transports Kongō Maru and Kokai Maru, along with the auxiliary minelayer Tenyo Maru were destined for Lae. The Japanese landed on 8 March 1942 at Lae and Salamaua. At Lae, the Japanese landed without opposition. A small detachment of the New Guinea Volunteer Rifles and the staff of the R.A.A.F. radio station at Salamaua set about the demolition of key infrastructure elements and then withdrew into the hills towards Mubo. Initial air interdiction by Hudsons from No. 32 Squadron and four B-17's from Garbutt were ineffectual.
In the early morning of 10 March 1942, Task Force 17 aircraft carriers Lexington and Yorktown launched their aircraft from the Gulf of Papua off the southern shore of New Guinea. The Task Force 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.
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 0922. They were soon followed by Dauntless dive bombers of Bombing Squadron 2 (VB-2) and the Douglas TBD Devastators of Lexington's Torpedo Squadron 2 (VT-2), which attacked shipping at Salamaua at 0938 while the Wildcats of Fighter Squadron 2 (VF-2) strafed Lae and Salamaua. Salamaua was struck again some 30 minutes later by Yorktown's Bombing Squadron 5 (VB-5), Torpedo Squadron 5 (VT-5) and Fighter Squadron 42 (VF-42), while the Dauntless dive bombers of VS-5 attacked the auxiliary ships along the shore at Lae.
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.
Three transports (Kongō Maru, Tenyō Maru, and Yokohama Maru) were sunk. In addition, the light cruiser Yubari, two destroyers (Asanagi and Yūnagi), the transport Kokai Maru, the minelayer Tsugaru, the seaplane tender Kiyokawa Maru, and the auxillery minesweeper Tama Maru No.2 were damaged. Tama Maru No.2 ended up sinking three days later due to damage inflicted by the raid. Two of the transport losses were awarded to the carrier aircraft, while the cargo ship was awarded jointly to the carrier planes and the B-17's.
The raiders lost one SB3-2 Dauntless dive bomber of VS-2, shot down from Japanese anti-aircraft fire. Two more SBDs were damaged and landed at Port Moresby on their way back. The remaining 101 of the 104 aircraft launched returned safely to their carriers.
The raid sank or damaged two thirds of the invasion transports employed. Higher casualties among the Japanese Army personnel were only prevented by the fact that most of the transports had been close to shore and could beach themselves. The psychologic impact was greater, putting the Japanese on notice that the Americans were willing to place their carriers at risk to oppose their moves in the region. The fear of interdiction by US carrier forces against future operations contributed to the decision by the Japanese to include fleet carriers in their later plan to invade Port Moresby, resulting in the Battle of the Coral Sea.