Heikko Antero Malkki, 59, was wounded in the early morning incident. He was taken to Vachira Phuket Hospital where he received 12 stitches to his left arm.
Phuket Town police said Mr Malkki was walking along Phang Nga Road, near the On On Hotel, at about 5.30am, after getting off a bus from Haad Yai when two man pulled over on a motorcycle and tried to steal his bag.
He resisted, and one of the men took out a knife and slashed his arm, before fleeing the scene.