For sure, it's a Thai coin; a 'satang' if between 15 and 18mm; or a 'baht' if between 20 and 26 mm. Most of the 'satangs' are of aluminum, the 'bahts' of a copper/nickle combinations. The image is of HM King Bhumibol Adulyade (Rama IX)--in his younger days-- if the coin is dated 1946 or later.
Don.....