Built in 1353 by King U-Thong who founded Ayutthaya, Wat Phutthaisawan originally formed a temporary lodging for royalty. It is older than Ayutthaya itself. This complex is located to the south of the island city of Ayutthaya, along the bank of the Chao Phraya River.

Set beside the river, this temple is particularly interesting as the modern functioning temple at the front of the complex contrasts with the intact older buildings in the middle and crumbling ruins at the rear.

The main attraction is the white Khmer style prang, surrounded by 105 seated Buddhas around the courtyard. Up inside the Prang, a black reclining Buddha can be found tucked away behind the central altar.

There is also a mural painted on a wall depicting Thai monks on pilgrimage to Sri Lanka in 1753 and 1755. A beautiful reclining Buddha rests outside of the compound on the eastern side.