What are the disadvantages of Ireland joining the EU?

Some of the disadvantages would be the way some laws are applied in Ireland. Some laws may not be so appropriate for Ireland, but are put in place. For doing business, there can sometimes be more restrictions because there is more competition from other companies in the European Union who are allowed to openly compete. As an island nation, Ireland's seas are important to it, but it has had to allow other countries access to Irish waters for fishing, causing some problems for the Irish fishing industry. However, there are many advantages too, and some of those make up for some of the disadvantages. Some of the above work the other way too, like Irish companies having more access to a wider market for them to compete in.