The Atlantic Ocean.
Ireland, by the Irish Sea
The Celtic Sea is to the south of Ireland and the Irish Sea is to the east of Ireland.
Lots of parts of Ireland are more than 20 miles from the sea. Nowhere would be more than about 80 or 90 miles from the sea. The conclusions that can be drawn is that Ireland is not very large compared to some countries.
No, there are no rivers in Ireland with deltas. Deltas are typically formed at the mouths of large rivers where they meet the sea, but Ireland's rivers do not have the necessary conditions for delta formation.
The sea between Britain and Ireland is the Irish Sea.
No, Ireland does not border the Mediterranean Sea.
Ireland is an island so it is surrounded by water. You are never more than about 70 miles from the sea in Ireland. Ireland also has a large amount of rivers and lakes, so some form of natural water is close to any point of Ireland.
It is the sea between Ireland and Britain and was named after Ireland, to become the Irish Sea.
The sea that separates Ireland and Northern Ireland from Great Britain is called the Irish Sea. The area of sea immediately north of the Irish Sea is called the North Channel, and separates Northern Ireland from Scotland.
Ireland is geographically part of the British Isles. So on that basis, there is no answer to the question. What you are referring to is the sea between Ireland and Britain. That is the Irish Sea.
Ireland is bordered by the Atlantic ocean to the West, and the Irish sea to the East.
The Irish Sea.