{ { Infobox military conflict
| conflict = Burmese–Siamese War (1809–1812) | partof = the Burmese–Siamese wars | date = June 1809 – January 1812 | image = ThalangWar.jpg | image_size = 300px | caption = Map showing the army routes.Green represents Burmese army routes.Red represents Siamese and –SiameseWar–Kedah army routes. | place = Junk Ceylon (Phuket), Southern Siam | result = Siamese victory; Phuket and many other Southern Siamese towns depopulated for several decades | territory = | combatant1 = Konbaung dynasty (Burma) | commander1 = Bodawpaya Atwinwun Nga Chan Thuriya Thaya Kyaw Nga U Thinka Thuriya Sibo Wun Toya Bo Zeya Thuriya Kyaw | combatant2 = Rattanakosin Kingdom (Siam) Kedah | commander2 = Rama II Prince Maha Senanurak Chaophraya Yommaraj Noi Chaophraya Nakhon Phat Phraya Chasaenyakorn Bua Phraya Thalang Thien Sultan Tajjudin Laksamana | units1 = Royal Burmese Army Royal Burmese Navy | units2 = Royal Siamese Army Royal Siamese Navy Kedah Army| | strength1 = October 1809 30,000 men60 war boats200 swivel guns
May 1810
6,000 men
December 1811
5,000 men|
| strength2 = 18 November 1809
Reinforcements including: 6,000 men0 war boats
May 1810 Unknown
December 1811
10,000 men|
| casualties1 = +4,110 men20 war boats|
| casualties2 = Unknown
}}
The Burmese–Siamese War (1809–1812) or the Burmese Invasion of Thalang was an armed conflict fought between Burma under Konbaung dynasty and Siam under the Chakri dynasty, during the period of June 1809 and January 1812. The war centered on the control of the Phuket Island, also known as Thalang or Junk Ceylon, and the tin rich Andaman Coast. The war also involved the Kedah Sultanate. This occasion was the last Burmese offensive expedition into Siamese territories in Thai history, with British acquisition of the Tenasserim Coast in 1826, following the First Anglo-Burmese War, removing several hundred miles of the existing land border between Siam and Burma. The war also left Phuket devastated and depopulated for many decades until its reemergence as a Tin mining center in the late 19th century.
Background
Since 1759, Siam and Burma have been in a near-constant state of conflict for over fifty years. In the late 18th century, the Burmese destroyed the Siamese capital at Ayutthaya and the city of Phitsanulok, the center of Northern authority for over two centuries. In turn, Burma has lost its Lan Na and Kengtung vassals to a resurgent Siamese regime. Large swathes of central Mainland Southeast Asia experienced severe depopulation as a result of the 50 year conflict.
King Bodawpaya of the Konbaung dynasty and King Rama I of the Chakri dynasty had engaged in several wars since 1785 including the Nine Armies' War (1785-86), the Wars over Tavoy (1792-93) and the Wars over Lanna (1802-1805). During the Nine Armies' War in 1786, the Burmese forces invaded Thalang or Phuket Island. Lady Chan, the wife of the late governor of Thalang, together with her sister Lady Mook, organized the defenses of Thalang and managed to repel the Burmese invaders. Lady Chan and Lady Mook were awarded with the titles Thao Thep Krasattri and Thao Si Sunthon, respectively. In 1789, Thien, a son of Lady Chan, became Phraya Thalang or the governor of Thalang.
In the early nineteenth century, there were two major settlements on the Phuket Island; the town of Thalang was the main town on the island situated on the central plains (modern Thalang District) and the port town of "Phuket Tha Reua" (not be confused with the modern city of Phuket, which was founded in 1827) situated on Ao Sapam on the eastern shore.
After many exhausting wars, the two kingdoms of Burma and Siam finally pursued diplomacy. In 1808, King Bodawpaya sent a diplomatic mission to Bangkok, who responded by sending reciprocal mission. Through these contacts, however, King Bodawpaya learned that most of the Siamese generals that had been active during the previous wars had already died. Prince Maha Sura Singhanat, the champion of many campaigns, had died in 1803. King Rama I himself was also in an old age. King Bodawpaya then initiated the new expedition to invade Siam.