The Thai Travel Agents Association (TTAA) is concerned about the slow vaccination plan and dependence on the tourism sandbox scheme to restart tourism within Asia by the fourth quarter.
Suthiphong Pheunphiphop, the TTAA president, said outbound travel will not start until the inbound market returns.
Yet several obstacles remain for foreigners wishing to visit Thailand such as limited flights, slow domestic inoculation programmes and travel bubble agreements.
Bilateral travel bubble agreements during the first stage of reopening are expected with several nations in Southeast Asia, China, Japan and South Korea.
The TTAA recently arranged a meeting with offices of other national tourist organisations in Thailand such as Japan National Tourism Organization, Korea Tourism Organization, and Singapore Tourism Board, as well as representatives from embassies including India, Indonesia and Nepal to receive updates about the travel policy of each country.
"Some of them showed interest in creating travel bubbles with us, but the main concern is the vaccination pace in Thailand as we're still struggling to secure sufficient doses to cover most of the country," said Mr Suthiphong.
The government expects to distribute at least 63 million doses by the end of the year, which covers less than half the population of 69 million. Most vaccines also require two shots.
Thai outbound travellers are not included on the priority list for vaccinations, so they have to wait until they are widely distributed.
He said the government should facilitate private hospitals and companies procuring vaccines once they are available for purchase, which would quicken the pace for herd immunity.
The Tokyo Olympic Games were considered an opportunity to kick-start outbound tourism, but they will not permit overseas spectators at the events due to virus concerns.
"Given that methods to restart outbound tourism activity are highly uncertain, it remains difficult to predict the number of outbound tourists this year," Mr Suthiphong said.
Thai outbound tourists might not exceed the 1 million recorded last year, assuming outbound travel restarts by the last quarter at the earliest, he said.