This year the vegetarian festival in Bangkok’s Chinatown runs from October 5th to the 14th, known in Thai as Tesagan Gin Je. The best place to experience this week long festival is in Phuket, but if you are in Bangkok, Chinatown is the place to hang out with plenty of street food stalls and donations at the temples in the Chinese quarter of Bangkok. Look out for the yellow and red flag which indicate they serve veggie food.
Tesagan Gin Je – Vegetarian festival in Thailand
Great article about my favorite thai festival here: http://discoverasean.com/thailands-v-fest/