Wat Si Pho or the "Monastery of the Magnificent Bodhi Tree" was located off the city island in the southern area of Ayutthaya in Samphao Lom sub-district.
The monastery was situated at the confluence of Khlong Takhian and the present Chao Phraya River. The monastery stood opposite Wat Khok Phlu and Wat Klang on the east bank of the Takhian Canal and as thus west of the Saint Joseph Church.
There are no traces anymore visible of the monastery above ground level.
Historical data about the monastery and its construction are unknown.
The site is only indicated on a mid-19th century map. It is plausible that the brick foundations of the Saint Joseph Church were designated as Wat Si pho, as later maps do not mention the latter. Until today, the eastern corner at the mouth of Khlong Takhian has not been excavated and as thus the existence of Wat Si Pho remained unconfirmed.