Two different sports that happen to share a start gun
Different Demands on the Body
A coastal race — flat or gently rolling, on road or firm track, exposed to wind but rarely to serious elevation — rewards a steady, efficient stride and a well-paced effort. A mountain race asks something else entirely: strong ascent, technical descent, and a pace that has almost nothing to do with a runner's flat 10k time. The two categories can share a distance on paper and feel like completely different efforts underfoot, and finishing times between them are rarely worth comparing at all.
Different Demands on Preparation
Coastal races are largely about managing wind and weather rather than terrain, and pacing strategy tends to look like a road race with a stronger headwind section built in. Mountain races demand specific preparation — hill sessions, technical descent practice, sometimes compulsory kit — because the consequences of being underprepared on exposed high ground are more serious than on an exposed coast road. Training for one does not automatically prepare a runner for the other, and a runner who arrives at a mountain event with only road miles behind them will usually feel the difference within the first climb.
Choosing Between Them
Neither is objectively harder; they're simply different disciplines wearing the same word. A runner drawn to the drama of the Atlantic coastline and the counties this book cross-references — Clare, Kerry, Galway, Donegal, Mayo, Sligo — might start with a signature coastal marathon or half before working up to something like the Kerry Way Ultra, which follows the full 200km Kerry Way through the Old Red Sandstone mountains in stages of 58km or more, or the Mourne Mountain Marathon on the other coast, a two-day team event over 35 to 55km through Northern Ireland's Mournes. Both belong to the mountain tradition properly organised in Ireland by the Irish Mountain Running Association, and both reward months of hill-specific training rather than road mileage alone. Most Irish runners eventually try both disciplines, if only because the same stretch of country tends to offer one within an hour's drive of the other.
From Running Ireland by F Cosgrove — a guide to the races of the island. Every race in the book is on our race map, county by county, with the month it usually falls in.