Officials say hospitals are increasingly forced to absorb treatment costs for uninsured tourists, Bangkok Post reported.
Authorities cite risky behavior among visitors as a major contributing factor.
In destinations such as Phuket, many tourists rent motorcycles without prior experience, often while under the influence of alcohol or drugs, heightening the risk of accidents.
The Ministry of Public Health estimates unpaid medical bills from foreign patients amount to at least 100 million baht (US$3 million) annually, with major tourism hubs such as Phuket and Chiang Mai most affected.
Hospitals are obligated to provide emergency care regardless of a patient's ability to pay, leaving them to cover the financial shortfall.
Data shows that road accidents remain a leading cause of hospitalization among tourists, particularly those unfamiliar with Thai roads.
Thailand recorded a slight decline in international tourist arrivals in the first quarter of the year, Nation Thailand reported.
From Jan. 1 to March 29, the country welcomed 9.1 million foreign visitors, down 2.29% year-on-year.