Undergarments for Running in Ireland: What Works in Rain, Wind, and Cold

When you’re out running in Ireland, your undergarments, the layer worn directly against the skin to manage sweat, temperature, and friction. Also known as base layers, it’s not about looking good—it’s about staying dry, warm, and free from chafing through endless drizzle and wind. Most people think it’s the jacket or shoes that make the difference. But if your undergarments fail, nothing else matters. You’ll feel cold even in a waterproof shell. You’ll get sore from rubbing. You’ll quit early because you’re just uncomfortable.

Irish runners don’t wear cotton. Not anymore. Cotton holds moisture like a sponge, and in a country where rain comes sideways and temperatures hover near freezing for half the year, that’s a recipe for shivering. Instead, you’ll see people wearing moisture-wicking underwear, synthetic or merino wool fabrics designed to pull sweat away from the skin and dry fast. These are the ones that stay close to the body without squeezing, don’t ride up during a long run, and don’t smell after three uses. Then there’s thermal undergarments, a thicker, insulated layer for winter runs when the wind cuts through your jacket like a knife. These aren’t for summer. But from October to April, they’re the quiet hero under your shorts or tights.

It’s not just about material—it’s about fit. Too loose, and it bunches. Too tight, and it cuts off circulation. The best ones for Ireland have flat seams, no tags, and a snug but comfortable cut that stays put whether you’re sprinting up Howth Head or trudging through a muddy trail in Galway. Brands like Under Armour, Lululemon, and even local Irish runners swear by merino wool blends—they’re soft, naturally odor-resistant, and handle dampness better than anything synthetic.

You’ll find people talking about compression tights, but that’s not always necessary. For most runners in Ireland, a simple pair of thermal shorts or leggings with built-in liner does the job. No need for extra layers unless you’re running in snow. And forget about boxers—they’re for lounging, not running. Briefs or performance briefs are the norm here. They stay put, reduce chafing, and don’t add bulk.

What you wear underneath affects everything: how long you want to run, how much energy you have, even your mood. A good pair of undergarments means you can focus on your stride, not your skin. It means you can run in the rain without feeling like you’re wearing a wet towel. It means you can head out in January and still enjoy it.

The posts below aren’t about fashion. They’re about what works when the weather turns ugly. You’ll find real talk from Irish runners about what they wear under their gear, what they’ve tried and ditched, and what actually keeps them moving through the worst of it. No fluff. No marketing. Just what fits, what works, and what keeps you on the road when everything else wants you to stay inside.