Last minute negotiations failed to save the 178-year-old holiday firm.
600-thousand tourists have been left stranded around the world after the collapse of Thomas Cook.
The British travel agent has ceased trading after failing to reach a deal with creditors.
It's estimated two and a half thousand Irish people are impacted.
Travel Expert Eoghan Corry says people who live near the border often use the travel agent to fly out of Belfast:
Peter Fankhauser, Thomas Cook's chief executive, said the firm's collapse was a "matter of profound regret".
Commenting as the company entered compulsory liquidation, Mr Fankhauser also apologised to the firm's "millions of customers, and thousands of employees".
The tour operator's failure puts 22,000 jobs at risk worldwide.
