It's a popular superstition that giving 10 baht back to someone you've robbed means the police will never find you.
The robber may have it wrong. Police have security camera images that show how he arrived at the Family mart in Lipon, in Phuket's Srisoonthorn district about 3.10am.
The man, wearing a pink raincoat, a helmet and a white mask, leapt the counter to get at the till.
He ran out and took off on a no-plate Honda Wave - then returned to hand over 10 baht.
Phuket police say he's welcome to come back and give them the rest of the cash anytime.