Abta has warned of “the potential risks and downsides” Brexit could have on UK holidaymakers.
The association has launched a report entitled What Brexit might mean for UK Travel, with economic analysis provided by Deloitte.
It notes that more than 29 million foreign holidays each year are made by UK holidaymakers to EU countries, equating to 76% of all holidays taken.
Additionally, 68% of all business trips, a total of 4.6 million, from the UK are to EU countries.
While the report admits it is unlikely that Brexit would have an immediate impact, it adds the UK benefits from a number of regulations and agreements as part of its EU membership that could go as a result of a departure.
These include financial protection for package holidays; compensation for flight delays; access to free health cover through the European Health Insurance Card; caps on mobile phone charges and "open skies" across the EU, resulting in more routes, more airlines, and lower fares.
More immediate concerns would be focused on the pound and the impact that departure would have, potentially making it weaker and more expensive to travel.
Abta chief executive Mark Tanzer said: “Our assessment of the report’s findings is that a vote to leave will lead to uncertainties and may lead to increased costs for travel businesses and the travelling public.
“We recognise that people will approach this referendum by considering many factors – personal, professional, and economic – before casting their vote.
“Abta has considered what a vote to leave the EU might mean purely from a travel perspective.
“Our view is that the potential risks and downsides are not matched by an equal upside for the traveller.”