As Ireland is a member of the European Union, Directive(EU) 2016/802 applies and a maximum of 0.10% sulphur fuel is to be used in port. Irish waters are not in a Emission Control Area defined by MARPOL Annex VI Regulation 14 and therefore the global limit of 3.50% sulphur applies to vessels except some passenger ships until January 1, 2020, when the limit will be reduced to 0.50%.  Passenger ships on regular voyages between EU ports (e.g. UK-Ireland ferries) are an exception, as subject to a limit of 1.50%S until January 1, 2020 under the EU Sulphur Directive.

A number of Irish ports have prohibited overboard discharges from exhaust gas cleaning systems to waters within their jurisdiction, citing the EU’s Water Framework Directive, 2000/60/EC and Environmental Quality Standards Directive, 2008/105/EC as the rationale:

Ship operators should check if other Irish ports are similarly regulated.