DUN Laoghaire businesses have said that the ending of Stena Line ferry services between the town and Hollyhead would be an "absolute disaster".
There are growing fears that the ferry operator will pull out of the town after it cancelled some of its sailings to the south-Dublin port for the Christmas period citing "commercial and operational" reasons.
A spokesperson from Dun Laoghaire Harbour Company said that discussions between the company and Stena Line over a revised service plan for next year "remain underway".
Locals fear that Stena Line may pull out of the harbour altogether.
Annette Doyle, who works in Lloyd's pharmacy, said that the cessation of Stena Line ferries would be "dreadful for all businesses in the area".
"It would be dreadful, especially for a pharmacy like us, where people off the boats come in and get the essentials they need while away from home. Around 70 shops have closed in the area over the last few years, and this would only make it worse," Ms Doyle said.
Local pubs would also feel the effects on sporting occasions, such as the Six Nations campaign, as Catriona Keegan - who works in Scott's Cafe Bar - explained.
"We have a lot of regular customers but when the likes of the Six Nations is on, you really notice the difference.
"You have English, Scottish and Welsh travelling over and they might even stay for up to a week at times," she said.
As well as the direct affect on industries, it would also have a severe knock-on effect for some shops.
Anne Joyce, who works at Costello flowers in Dun Laoghaire, believes the drop in visitors from Stena Line services would affect local businesses, leaving less money in the area to spend.
However, other businesses wouldn't feel the pinch too much if the UK Ferrier cancelled its service.
General manager of Mao restaurant, Lenka Dorcakova, said that her business mainly depends on locals eating there.
"Most of our customers are local, so I don't think the restaurant would be too affected by it," she said.
Dun Laoghaire Harbour has plans to expand its cruise ship service next year, hoping to bring more than 100,000 passengers to the Dublin east-coast town.