Bombing of Bangkok in World War II

Japanese air attacks

Military targets at and near Bangkok were first attacked by 3rd Air Group's (第三航空隊) Mitsubishi Ki-30s of the 31st Sentai under Lt Col Hayashi Junji as part of the Japanese invasion of Thailand. Prior to the start of the invasion, fighters from the 77th Sentai and bombers of the 31st Sentai moved to Siem Reap close to the Thai border. On the morning of 8 December 1941, they were ordered to attack Aranyaprathet airfield on their way to Bangkok. Nine 31st Sentai bombers, escorted by 11 Nakajima Ki-27s of the 77th Sentai led by Japanese air ace Major Yoshio Hirose (広瀬 吉雄), headed for the Thai capital. On their approach they were intercepted by three Thai Air Force Curtiss Hawk III fighters from 43 Squadron. These were flown by Flight Lieutenant Chin Chiramaneemai, Flight Lieutenant Chai Sunthornsing and Flying Officer Sarit Potivetchagul and were based at Watana Nakorn airfield in Prachinburi Province. They had been advised not to engage the superior aircraft, but they took off anyway as a matter of national pride. Major Hirose, Lieutenant Yoshiro Kuwabara and Lieutenant Tsuguo Kojima shot down all three planes, killing the Thai pilots. This was the only air raid during the Japanese invasion of Thailand, since the Thai government of Field Marshall Pibunsongkhram acceded to Japan's demands by 13:00 that same day, although fighting continued much longer on the ground until the cease fire was announced. On 21 December 1941, Thailand signed an alliance with Japan. On 25 January 1942, the Thai government declared war on the United States and the United Kingdom, although the regent refused to sign it in the name of the young king (who was studying in Switzerland). On December 8, 1941, at dawn, the Japanese forces invaded the eastern part of Thailand. Sentoki fighter aircraft attacked Wattana Nakhon Airfield, damaing the control tower, buildings and the runway. The other point of invasion was Wing 5, Prachuap Khiri Khan Province. Officers, enlisted men and conscripts numbering 120 under the command of Wing Commander Mom Luang Prawas Jumsai withstood the attack with bravery. Over four hundred Japanese soldiers were killed while forty men at Thai side died in the battle and only four suffered casualties. The fighting went on until the Government ordered a cease fire. RTAF (Royal Thai Air Force) personnel assisted the resistance against the Japanese. After World War II, the Thai Air Force sent three C-47s to support the United Nations in Korean War. During World War II Japan ask Thai Air Force joining occupying part of Burma.

Initial British and American air raids

Allied bombing raids on the Thai capital city of Bangkok began even before Thailand had declared war, since the Empire of Japan was using the country as a staging area for its invasions of both Malaya and Burma, with the reluctant agreement of the Thai government after Japan's successful invasion of the southeast Asian country. The first raid came on 7 January 1942, when Royal Air Force (RAF) aircraft flying from Rangoon, attacked military targets in the city. The American Volunteer Group, together with seven No. 113 Squadron RAF and three No. 45 Squadron RAF Bristol Blenheim bombers, were involved in the first raid. No. 113 Squadron's planes were piloted by No. 60 Squadron's air crew. The second night raid was carried out by eight Blenheims on 24–25 January and included No. 60 Squadron RAF aircrew. A final raid was made three days later by four Blenheims. This was the last raid by Blenheims until May or June 1945.

After Rangoon fell to the Japanese on 7 March, heavy bombers, such as the RAF and American Tenth Air Force Consolidated B-24 Liberators, based in India and China, attacked Thailand. The raids were carried out because Bangkok by then had become a command centre for the Japanese on the Southeast Asian front. RAF and USAAF bombers carried out the raids as part of the Pacific campaigns. The bombers targeted installations used by the occupying Japanese military, but the raids were also intended to pressure the government of Thai military strongman Plaek Pibulsongkram to abandon his unpopular alliance with Imperial Japan. The major targets were the newly completed Port of Bangkok and the Thai railway system. Raids by RAF, USAAF, and other Allied air forces continued with growing intensity from India, and after the liberation of Rangoon on 3 May 1945, from Rangoon until the end of the war in August that year. Blenheim bombers and Mustangs operated out of Rangoon against Bangkok in this later phase of the bombing.

First B-29 Superfortress combat mission

In its first combat mission, the American Boeing B-29 Superfortress was used by the XX Bomber Command's 58th Air Division to strike targets in Bangkok, before it was deployed against the Japanese home islands. The decision to use the B-29s to bomb Bangkok dated back to 1943 and was mentioned in a communique between US President Franklin D. Roosevelt and British Prime Minister Winston Churchill in which Roosevelt suggested that they be used to bomb the port and railways.

On 5 June 1944, 98 B-29s led by the 58th's commander, General LaVerne Saunders, flew out from airfields in India to attack the Makasan railway yards in Bangkok. The raid was the longest distance mission to that date in the war. It was a 2,261-mile round trip. Only 77 of the B-29s made it to Bangkok, with 21 having had to return home because of various engine problems. Arriving at the Thai capital at about 11:00, the bombers found the target obscured by bad weather which in turn caused an element of confusion in the attack. The B-29s were meant to have dropped their bombs from between 22–25,000 feet altitude but instead did so from between 17–27,000 feet. Only 18 bombs hit their intended targets. The others destroyed a Japanese military hospital and damaged the Japanese secret police headquarters. On the return leg, 42 B-29s had to divert to other airfields because of a lack of fuel and five crashed on landing, although none were lost to enemy fire. Further raids were carried out by the Superfortresses against strategic targets in Bangkok.

Temporary British occupation

At the end of hostilities the RAF set up a headquarters in Bangkok, at Don Mueang airfield, under Group Captain Don Finlay on 9 September 1945. The headquarters was from No 909 Wing RAF. Three RAF squadrons were represented in Siam during the brief occupation: No. 20 Squadron RAF with Spitfire VIII aircraft, No. 211 Squadron RAF with de Havilland Mosquito VI aircraft, and a detachment of No. 685 Squadron RAF with Mosquito photo-reconnaissance aircraft. The airfield was defended by No. 2945 Squadron, RAF Regiment. Almost all the RAF units had left by January 1946.