The Brazilians were followed by the Swiss as the highest paying Europeans, at 4,123 baht after a 3% increase in tariff payment recorded in 2012, according to the latest the Hotels.com's Hotel Price Index.
The third rank on the list went to the Chinese, the most generous in Asia, at 3,876 baht, following a 2% increase, according to the online hotel booking website Hotels.com.
Zoe Chan, head of PR at Hotels.com Asia Pacific, said: "The data have shown that Chinese travellers' spending has been increasing and it's exciting to see it now ranks among the top-three in this global list."
Amongst the other most important inbound source markets to the country, the Malaysians paid an average 4% less from the previous year, at 2,654 baht and ranking 37th, while the Russians were at 19th at 3,327 baht after a 15% fall.
The highest risers in the report were the Mexicans, up 21% to 3,853 baht in the fourth place, followed by the Italians, up 13% to 3,026 baht at the 29th place, and the Danish, up 9% to 3,270 baht at 21st.
Other significant fallers included the Spanish, down 15% to 2,734 baht at 36th, and the bottom of the table, the Vietnamese, down 13% to 2,188 baht.
Average price paid for a hotel room in Thailand in 2013 compared with 2012 by visiting country.