Tour operators hope outbound tourism will bounce back in the last quarter of this year after slowing down the past few months because of the sluggish economy.
The Thai Travel Agents Association (TTAA) said the outbound tourism business had been affected by the country's economic slowdown caused by falling exports the past few years.
With their confidence hit, many customers will wait to travel in the coming high season starting in October, said the TTAA.
Outbound tour package sales have dropped 10% since the second quarter.
Moreover, travel companies saw their outbound tour package prices drop 10-20% since April, which should drag on until the end of the third quarter, said Suparerk Soorangura, the TTAA president.
"Many travel agents must sell tour packages without making a profit. They will do this to survive until the high season comes," he said.
The TTAA projects demand from private companies remains strong as many of them will use overseas trips as a reward to persuade their staff to work harder.
"I think key challenges for Thai tourism the rest of the year are movements in foreign exchange, local politics and economic sentiment," Mr Suparerk said.
For example, Britain's decision to leave the EU caused the pound to depreciate 2% against the Thai baht. If the pound weakens by 5% against the baht, package tour prices to Britain will decrease significantly, he said.
The stronger yen against the Thai baht has already affected many tour agents because they sold package tours without using currency hedging. However, Japan is still the hot destination among Thai travellers, with projected growth of 25% this year, likely recording 1 million visitors, surpassing China and South Korea.
The TTAA forecast some package tour prices to Japan would increase slightly at the 19th International Travel Fair 2016, which will be held from July 14-17. The association expects 300,000 visitors will visit the four-day fair, generating around 400 million baht.
Mr Suparerk said the association hoped to maintain the number of outbound Thai tourists at 7 million this year, with their total spending overseas at 210 billion baht.
For domestic tourism, PK Exhibition, the organiser of the 39th Thai Tiew Thai fair from June 30-July 3, is optimistic because of a marketing campaign by the Tourism Authority of Thailand.
Krit Patarapal, managing director of PK Exhibition, said he was confident Thailand would reach the government's domestic tourism target of 140 million trips and 900 billion baht in revenue this year.
The previous Thai Tiew Thai fair held in March drew 550,000 visitors and generated more than 300 million baht in income.
The new fair is scheduled for Bitec Bang Na, running from today until Sunday. It is projected to welcome some 100,000 visitors, generating tourism income of over 200 million baht.