The strong baht is expected to affect the tourism industry as travellers may shift to other destinations in the region where local currencies have edged up at a slower pace, said a business leader.
Vichit Prakobkosol, president of the Association of Thai Travel Agents (Atta), said the baht has appreciated against the US dollar by around 4% since the start of this year, outperforming other regional currencies.
He said the rise will hurt tourism as foreign travellers have to pay more while travelling here, pushing them to other Asean countries where currencies have appreciated more moderately.
At the start of this week, the Malaysian ringgit had risen 1.5% against the dollar, while Indonesia's rupiah strengthened by 2.2%. Singapore's dollar was up 0.9% versus the US dollar, while the Filipino peso increased 0.7%, and the baht gained 3.8%.
The baht's appreciation is one cause for the decrease in tourists that used Atta members services in all markets last month, said Mr Vichit.
In January alone, the number of international arrivals that used Atta member services plunged by 11.6% to 492,907, down from 557,305 in the same month of last year.
Statistics show big drops from Middle Eastern countries, which dipped 47% year-on-year; Africa, which contracted 28%; the US, down 20%; Europe, a loss of 12%; and China, down 11%.
Last year, foreign tourists served by Atta's members at Suvarnabhumi and Don Mueang airports stood at 5.58 million, a slight decline from 5.82 million in 2017.
Mr Vichit, who was reelected on Wednesday as Atta president, said members that operate inbound tours are concerned that if the baht continues to appreciate, it will affect operators' performance as stiff competition is preventing them from marking up the prices of package tours.
The strong baht does benefit Thais travelling abroad, but operators of outbound tours say the business is still tepid, especially for March, as there is no long holiday and they do not earn much from currency exchange as most packages are sold in baht.