Approximately 100 miles.
Fishguard is in Wales, not Ireland. You'll need to take a ferry to get from Fishguard to Dublin or Vice Versa. There are daily ferries, they take a few hours.
About 100 miles or 160 kilometres.
The distance between Dublin and Derry is 147 miles (236 KM) with travelling time approx 3.5/4.0 hours by road.
It is about 194 kilometres or about 120 miles.
It is about 100 miles or 160 kilometres.