The Tenby marathon: 42km of hills, cobbles and a wall of crowd noise

It's not a flat marathon

Let's be clear from the start: the IRONMAN Wales run is not your classic fast end-of-race marathon. The course runs over roughly 4 laps through the streets of Tenby and along the seafront — lap count to be confirmed on the 2027 map — and it's genuinely hilly: one guide lists over 400m of total elevation gain. Kickers, descents, cobbled streets through the old town. After 180km on the bike with 2,400m of climbing, every little rise counts double.

The course, lap by lap

The lap format has pros and cons:

• Pros: you know the course from the second lap onwards, you can break the race into mental chunks, you see your family multiple times, and aid stations are frequent and close together.
• Cons: you hit the same kickers four times, and you know exactly what's coming. Your head needs to be ready.

The cobbles in the town centre deserve attention: they get slippery in the rain, and late in the race your foot placement isn't as precise as it was at km 5. Shoes with good traction and cushioning are a sensible choice; this is not the day for minimalist racing flats, unless you're very light and efficient.

The crowd: fuel and trap

The support in Tenby is one of the reasons this race is famous. The town is compact, the course passes through the centre multiple times and the finish square is bedlam. It's brilliant. And it's dangerous: plenty of athletes go out too hard, carried along by the noise. The rule: for the first 10km, run slower than feels right. The hilly course makes per-kilometre splits unreliable, so manage by perceived effort or heart rate, not raw pace.

Pacing on a hilly course

Three concrete principles:

1. Walk the steepest kickers if you need to, right from lap one. Walking for 30 seconds uphill costs less than blowing up at km 32. It's not giving in, it's strategy. 2. Don't surge on the descents. Steep downhills late in the race wreck your quads. Descend under control. 3. Break the race into laps, not kilometres. Four mental blocks of roughly 10.5km are easier to manage than an abstract 42km.

If you're chasing a time (4:40 for sub-13, 4:05 for sub-12 in our rough pacing tables), add a margin to your reference marathon time from a flat course: the climbing and the cobbles take their toll.

Aid stations: frequent, but bring a plan B

Aid stations around the lap are frequent — one advantage of the town-centre format. But in the past, some athletes have reported certain products running out late in the run, when the slower athletes come through. The takeaway is simple: don't build your nutrition around the aid stations. Carry the gels you need, tested in training, and use the aid stations for water and extra top-ups. If you're in "happy finisher" territory (a 5:30 marathon), this advice matters even more.

Weather: dress for the worst

In mid-September it can rain, blow a gale and be cold — sometimes all at once. Put two scenarios in your run gear bag: a lightweight top for sunshine, but also arm warmers or a light windproof layer for rain. Running four hours soaked and freezing along the seafront is not a theoretical scenario around here.

How to prepare for it

• Long runs on hilly routes, not just the flat: your body needs to learn to change footstrike and rhythm.
• A few sessions on cobbles or uneven ground, if you can, to condition ankles and feet.
• Bike-run bricks with the bike ride done on climbs: the legs you'll have in Tenby will be those legs, not fresh ones.

What to do now: decide your hill strategy today (run everything or walk the kickers?) and test it on a long run. Don't improvise on race day.