The snake in the image has a bright green coloration, which is characteristic of certain species found in Thailand. Based on this color, a common species is the green pit viper (genus Trimeresurus or Cryptelytrops). In Thailand, these green pit vipers are often found in gardens, forests, and near human dwellings.
However, if this snake was identified in a more controlled, artificial setting, like a garden or a pot, it could also be a non-venomous species, such as a green bush snake (Ahaetulla nasuta), which is harmless to humans and commonly found in Southeast Asia.
Since identification can be challenging from just an image, especially without seeing the head or specific body markings, exercise caution around green snakes in Thailand, as green pit vipers are venomous. It’s best to consult a local expert or wildlife authority for a precise identification if you encounter a snake like this.