Pratuan Muanroong contacted the FM91 station to contact the tourist, Watanabe Tesuro, 56, to retrieve the suitcase at the station.
He transported Tesuro from the Suvarnabhumi International Airport to Soi Thaniya in Silom at 1 am Monday and he forgot the bag.
The Japanese man gave 200,000 yen to the taxi driver as a reward.
The Nation