Based in Samut Prakan, Underdog Microbrewery is southeast of central Bangkok, but beers can be found in various bottle shops and bars.

Underdog Microbrewery around town
Underdog is an active brewpub and can be found at their own brewery and are often found at different beer fests, such as in the picture.
Underdog is listed as one of Bangkok’s BrewPubs.
From the Untappd Profile:
“At the heart of Samut Prakan’s bustling industrial landscape, Underdog MicroBrewery emerges as a beacon of craft beer innovation. We take pride in being the trailblazers with the first pub license in the area, introducing a collection of 20 distinctive craft beers directly from our taps to your glass. Samut Prakan, a thriving hub at the edge of Bangkok, is a melting pot of hardworking individuals from across Thailand, all drawn here by the promise of opportunity. It’s a place known for its gritty subcultures, like the daring youth motorcycle gangs, symbolizing a fearless zest for life that inspires us every day. Underdog isn’t just for craft beer aficionados; it’s a community favorite, resonating with the local vibe and the people who make Samut Prakan unique.”