The services from London, Birmingham and Manchester go to Dublin, Belfast and Cork and are available to book at www.eurolines.co.uk
John Gilbert, President of Eurolines said: "We were advised about the ash cloud this morning and immediately began adding extra capacity to our coach services.
We've made 300 additional coach seats available on services to Ireland to help minimise the impact this new alert will have on people's travel. We'll continue to monitor the situation and will increase capacity further to meet demand and help passengers get to their destinations."
Services to Dublin and Belfast depart from London Victoria and Birmingham Coach Station.
Eurolines is also operating to France as the Eurostar continues to experience difficulties this morning. Eurolines is Europe's largest coach service network and group's together 32 independent coach companies taking passengers to over 500 destinations across Europe. All Eurolines members use modern coaches with reclining seats, large picture windows, toilet facilities and a comfortable amount of legroom. All services are non-smoking.