We survived volcanic ash and Sars, but this is a real threat, say hoteliers
Howard Hastings is the managing director of family owned Hastings Hotels, which co-owns the Merrion Hotel in Dublin and employs 800 full-time and 800 part-time staff in Northern Ireland.
Business is very good for Mr Hastings. The drop in the value of sterling means visits to Northern Ireland are cheaper for those travelling from the Republic. As well as taking regular breaks, visitors are crossing the Border to buy cheaper second-hand cars and for dental treatments.
"For now, the currency is having a benign effect that makes it more competitive against the Republic price wise," he said.
However, Mr Hastings said the possibility of restrictions like work permits on hiring staff is concerning him.
"We want to avail of the widest possible labour market. If it was more restrictive for people to get work permits from the EU or, heaven prevent, the Republic, it would be a retrograde step."
He worries tourism will be way down the pecking order when it comes to the UK government's focus. "To an extent, our fortunes are inextricably linked to our trading partners in the Republic. We have a common cause to prevent restrictions," he said.
Joe Dolan is owner and manager of the Bush Hotel in the centre of Carrick-on-Shannon, Co Leitrim, which dates back to the 18th Century. He employs 69 employees and is currently president of the Irish Hotels Federation.
Mr Dolan admits he is "uneasy" about business prospects. "I've seen all the other things in the past - foot-and-mouth and Sars and volcanic ash, but believe me, once you had three weeks clear, it was tangible and you knew it was over. Brexit is just unchartered waters."
Situated not far from the Border and highly dependent on Northern Irish business, a soft Border and maintenance of the common travel area are crucial to him.
"Two nights and a dinner - the grey market - that's very important to us," he said.
"A lot from Northern Ireland come down for that but now it's 12pc to 15pc more expensive."