One of the best Jazz-pubs in Thailand is the well-known The Bamboo Bar located at the Oriental Bangkok Hotel. The bar has ambiance with its marble and dark-wood with low lighting. The pub was clearly designed to be a walk back to colonial times in Thailand. Very stylish and well worth a visit.
The Bamboo Jazz bar has live music every night except on Sundays when they do not have a live singer and it becomes more of a jam session. They do invite some of the best Jazz artists around such as Chet Baker and John Coltrane and others. The jazz bar is easy to find and you can take the train to the BTS Saphan Taksin station and across the road from the French Embassy in Bangkok. The bar opens at 6 in the evening and the live music starts at 9 in evening from Mondays to Saturdays. See the map below.