Thomas Cook staff in Grafton Street have started a sit-in protesting the decision to close the Irish operation a month ahead of schedule.
According to staff, the Thomas Cook shops in Grafton Street and North Earl Street were due to close at the end of August with the loss of 70 jobs.
The company has been in Ireland for 125 years.
Staff have rejected the company's redundancy offer and decided to take action to oppose the closure.
A demonstration was held on Wednesday on O’Connell Street where the staff were sharply critical of the company owner Manny Fontenla Novoa and his decision to end the Irish operation.
A Thomas Cook spokesperson said that following more than two months of consultation, the company had reached the decision to close the two shops 'with regret'.
Nick Sandham said that the company had considered several alternatives to make the two stores profitable but 'unfortunately these have not proved to be viable'.
As a result, the Grafton Street and North Earl Street stores will close today.
Mr Sandham said that the priority is to contact customers with bookings made through the two stores to let them know how to contact the company and make arrangements for the collection of travel documentation.