The incident occurred in front of a bar at about 12:20am, the victim told police.
The tourist, identified as Guilherme Rodrigues e Almeida Fernandes (nationality not reported), told police that his 10-gram gold necklace was stolen by two individuals.
Mr Fernandes said he went to Soi Bangla looking for a place to sit and have a drink. When he arrived at the entrance of Soi Bangla, he encountered two men dressed as women.
The first man, wearing a green dress, was chubby and had a small moustache. The second man, in a white dress, was thin. Both men tried to invite the victim to join them for a drink, but the victim declined and continued walking into Soi Sea Dragon.
In front of a shop called Harem, the man in the green dress approached the victim again, trying to talk and touch him. He grabbed Mr Fernandes’s shoulder and hugged his neck, while the second man in the white dress followed closely behind. The victim told them to stop following, and eventually, both men walked away.
Later, as Mr Fernandes left Soi Bangla, and realised his necklace with 10 grammes of gold was missing. Convinced that the two men had stolen it during the encounter, Mr Fernandes returned to the area to search, but the two men had disappeared.
Police said officers were reviewing CCTV footage from the area and gathering additional evidence.