Bombing of Bangkok in World War II Bangkok was bombed by both the Japanese and Allies during World War II . It was also the target for the first combat mission by Boeing B - 29 Superfortress es in June 1944 . Japanese air attacks . Military targets at and near Bangkok were first bombed by 3rd Air Group ' s ( 第三航空隊 ) Mitsubishi Ki - 30 ' s 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 December 8 , 1941 , they were ordered to attack Aran Pradet airfield near Bangkok . Nine 31st Sentai bombers , escorted by 11 Ki - 27 s of the 77th Sentai led by Japanese air ace Major Yoshio Hirose ( 広瀬 吉雄 ) , headed for Bangkok . As they approached they were intercepted by three Thai Air Force Hawk III fighters from 43 Squadron . These fighters 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 . Major Hirose , Lieutenant Yoshiro Kuwabara and Lieutenant Tsuguo Kojima shot down all three planes . This was the only bombing raid during the Japanese invasion of Thailand because the Thai government acceded to Japan ' s demands by 1 : 00 pm that same day . An alliance was signed between Japan and Thailand on December 21 , 1941 . On January 25 , 1942 , the Thai government declared war on the United States and the United Kingdom . Initial British and American air raids . Allied bombing raids on the Thai capital city of Bangkok began before Thailand had declared war because the Empire of Japan was using Thailand as a staging post for its invasions of both Malaya and Burma with the agreement of the Thai government . The first raid came on January 7 , 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 Blenheim bomber s , 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 with 8 Blenheims on 24 – 25 January and also 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 March 7 , heavy bombers , such as RAF and American Tenth Air Force B - 24 s , based in India and China attacked Thailand . The raids were carried out because Bangkok was a command centre for the Japanese on the South East Asian front . RAF and USAAF bombers carried out these raids as part of the Pacific campaigns . The bombers targeted installations useful to the occupying Japanese military , but the raids were also intended to pressure the government of Thai military strongman Plaek Pibulsongkram to abandon his 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 May 3 , 1945 , from Rangoon up 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 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 for using the B - 29s to bomb Bangkok dated back to 1943 and was mentioned in a communicate 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 am , 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 Muang airfield , under Group Captain Don Finlay on September 9 , 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 .