Wat Mai or the “New Monastery” is a restored ruin located off the city island in the northern area in Khlong Sra Bua sub-district. The monastery was located on the junction of Khlong Sra Bua and Khlong Muang (the old Lopburi River), opposite respectively Wat Na Phra Men (active temple) and the Grand Palace (restored ruin).
The temple complex faces south towards the Lopburi River as most of the temples along this city canal. It is customary in South and South-east Asia that the monastic structures are aligned in an east-west axis and that the principal building faces east, the direction of the rising sun and representation of life. In this case another important consideration played a role which is, that a temple should face water, explained by the fact that the Buddha attained enlightenment sitting under a Bo tree facing a river.  The temple can face south, as south has a neutral value in the cosmological alignment.
In situ are the remains of an ordination hall or ubosot (Th) and a number of satellite chedi. The monastery was surrounded by an outer wall. According to archaeological evidence the monastery dates from the Late Ayutthaya period (1629-1767) and could have been in use even in the Early Ratanakosin (Bangkok period). 
Alfons Van der Kraan state in Ref  it was probably this temple that Jeremias Van Vliet mentioned in his “Diary of the Picnic Incident”, although - but less likely - it could have been Wat Mai (Wat Bang Kaja), which is indicated on Valentijn’s map (1726). Less likely, because Wat Na Phra Men was known as a Royal cremation ground for the highest rank, and the Phraya Nakhon Ratchasima (Oya Corassima - see text here under) and his mother were likely related to the King. It could have been that Wat Mai was used as a substitute of Wat Na Phra Men for the funeral rites of lower rank.
"On December 18 , the Shahbandar, Olong Tsiut, and I went to the Berckelang. Upon arrival, we (and everyone else who had some business there) were told that His Honor had gone to the temple Watmoey to assist in the cremation of the mother of the deceased Oya Corassima". 
Historical data about the monastery and its construction are unknown.
 The Lord of the Golden Tower - Beth Fouser (1996) - page 36/37.  Fine Arts Department (FAD) sign in situ.  Van Vliet's Siam - Chris Baker, Dhiravat Na Pombejra, Alfons Van Der Kraan & David K. Wyatt (2005) - page 71.
Text & photographs by Tricky Vandenberg - November 2009