The sentencing of Chumpol Khaonuang took place on Thursday, said Lieutenant Amornrat Sudthikerd of Krabi Police Station.
It's believed Chumpol has appealed against the sentence.
The judge imposed a 15-year sentence for the rape of a 19-year-old Dutch woman near Ao Nang after her birthday party. He added an extra five years because the accused had been jailed and convicted for a murder at the age of 17.
It's believed that the victim and her father, a Dutch musician, were content with the 20-year sentence.
The father composed a song called 'Evil Man From Krabi' and posted it on YouTube when it appeared that Thai police were reluctant to pursue the case.
The song became a viral hit, attracting more than 500,000 viewers and generating worldwide interest in the case.
The father attributed some of the success of the case to Bangkok-based journalist Andrew Drummond, who was the first to report what had happened in detail.
Chumpol, a 32-year-old tour guide, has been unable to raise bail set at 700,000 baht.