Established in 1997, the Londoner Brewpub is the city’s oldest brewpub, located east side of central Bangkok on the way to the airport, and is a destination for great food, drink, and music.
Although Bangkok has an increasing number of brewpubs, but the Londoner will remain the city’s oldest.
– Brewpubs page found here

Live Music, Brunch, and Roasts
The Londoner has live music and brunch specials, often including live music, on the regular. Good idea to check their Facebook page for upcoming events and live performances.
Getting to The Londoner Brewpub
Address: 1178 Phatthanakan Rd, Suan Luang, Bangkok 10250. Soi 32/1 Phatthanakan Rd.
Londoner on Google Maps