How to Choose a Wetsuit

If you have ever waded into the Irish sea in July and felt the cold bite straight through you, you already know why a wetsuit matters. Our water is beautiful and it is cold, even at the height of summer, and the right wetsuit is the difference between a quick, gasping dip and an hour of actually enjoying yourself. The good news is that choosing a wetsuit is not complicated once you understand what the numbers on the label mean. This guide covers how to choose a wetsuit for Irish conditions, from thickness and fit to the accessories that let you swim and surf well past the warm weeks.

At 53 Degrees North we stock wetsuits from O'Neill and Ripcurl for everyone from first-time sea swimmers to regular surfers, in every thickness you are likely to need here. Work through the decisions below in order and the right suit becomes clear.

It starts with the water, not the calendar

The single thing that decides what wetsuit you need is water temperature, not the date or the air temperature. Irish and Atlantic waters sit at around 9 to 10°C through late winter and spring, and climb to the mid-teens, roughly 13 to 16°C, at the peak of summer in August. That is cold enough year-round that bare skin is a short-lived idea, and warm enough in summer that you do not need a heavy winter suit to enjoy a swim. Knowing the rough temperature of the water you will spend most time in is the starting point for everything that follows.

What the thickness numbers mean

Wetsuit warmth is measured by the thickness of the neoprene, in millimetres, and you will almost always see it written as two numbers, like 3/2 or 5/4. The first number is the thickness around your core, the chest, torso and back, where keeping warm matters most. The second is the thickness at your arms and legs, kept thinner so you can move and paddle freely. So a 3/2 wetsuit has 3mm of neoprene over the body and 2mm at the limbs. The thicker the neoprene the warmer the suit, and the less flexible it is, which is why the warmth is concentrated where you need it and the stretch is kept where you move.

Matching thickness to Irish water

Here is how those numbers translate to the water you will actually be getting into here. A 2mm springsuit or shortie is a summer-only choice for the warmest, calmest days, when the water is up around 17°C and above. A 3/2 full suit is the Irish summer staple, comfortable through roughly 12 to 17°C, which covers most swimming and surfing from late spring into early autumn. A 4/3 full suit is the genuine all-rounder, a little warmer and good down to around 9 to 11°C, and if you only buy one suit to use across most of the year, this is the one. Once the water drops below about 10°C, into winter and serious cold-water dipping, you want a 5/4 suit, ideally hooded, with boots and gloves to match.

If you are not sure between two thicknesses, size up to the warmer one. It is far easier to enjoy the water in a suit that runs slightly warm than to cut a session short because you are cold.

Full suit, springsuit or shortie?

Thickness is only half the story, the other half is how much of you the suit covers. A full suit, also called a steamer, covers you to the wrists and ankles and is what most people in Irish water will want most of the year. A springsuit or shortie has short arms, short legs, or both, trading warmth for freedom and a cooler, lighter feel on warm days. For our climate a full suit is the sensible default, with a shortie as a nice-to-have for the handful of genuinely warm summer sessions rather than a first purchase.

Zips and seams: the details that keep water out

Two construction details affect how warm and watertight a suit is. The zip is the obvious one. A back zip is the most common and the easiest to get in and out of on your own, with a slight trade-off in that a little more water can trickle in at the neck. A chest zip is harder to wriggle into but seals better and keeps you warmer, which is why colder-water suits often use one. The seams matter just as much. Flatlock seams, where the panels are stitched flat, are comfortable and fine for warmer-water summer suits, but they let a little water through. Glued and blind-stitched seams, often shortened to GBS, are bonded and far more watertight, which is what you want in anything you will wear in cooler water. The warmest suits go a step further again and seal the seams with liquid tape.

Getting the fit right

A wetsuit works by trapping a thin layer of water against your skin and letting your body warm it, so fit is everything. The suit should be snug all over, with no loose folds and no pockets of air, especially at the lower back, the chest and behind the knees, because any gap fills with cold water that never warms up. At the same time you need to be able to reach your arms overhead and breathe comfortably. A new suit will always feel tight and slightly awkward on dry land, that is normal, and the neoprene gives a little once you are wet and moving. If you are between sizes, the snugger option is the warmer one, as long as you can still move freely.

Sea swimming and cold-water dipping

For sea swimming, a 3/2 covers the summer comfortably and a 4/3 stretches your season into spring and autumn. Cold-water dipping, the quick, bracing winter swims that have become so popular around the Irish coast, is a slightly different game: many dippers are in and out quickly and pair a 4/3 or 5/4 with boots, gloves and a warm changing robe for the all-important warm-up afterwards. The longer you intend to stay in, the more warmth you will want.

Surfing and watersports

Surfing asks more of a suit because you spend a lot of the session sitting still in the water waiting for waves, losing heat, then needing full flexibility to paddle and pop up. That combination of warmth and stretch is exactly what the O'Neill and Ripcurl surf ranges are built for. A 3/2 or 4/3 with good flex covers most of the Irish surfing year, with a hooded 5/4 for committed winter sessions.

Kids in the water

Children feel the cold faster than adults, so do not skimp on their suits. Look for an easy entry system, a back zip or a simple step-in design, because a fight to get a damp child into neoprene takes the fun out of a beach day quickly. Sizing is the main challenge, a suit wants to be snug to work, but kids grow, so check the measurements rather than guessing by age. You will find children's suits within our main wetsuits range.

One suit to start with

If you would rather skip the deliberation and buy the one suit that does the most, a 3/2 full suit is the right answer for most people getting into Irish water. The O'Neill Reactor-2 3/2 is a great example, a flexible, fairly priced full suit that handles the bulk of the swimming and surfing season here, with women's and youth versions in the same line. Start here and add a thicker suit or accessories later if you find yourself chasing colder water.

The accessories that stretch your season

Once the water cools, accessories do more for your comfort than another millimetre on the suit, because your hands, feet and head lose heat fastest. Neoprene boots keep your feet off cold ground and stop them going numb, gloves keep your fingers working, and a hood makes a surprising difference on the coldest days. A Dryrobe or changing robe is the other quiet hero, letting you change in a car park and warm up fast after a cold swim. These are the pieces that turn a three-month season into a year-round one.

Ready when you are

Choosing a wetsuit comes down to the water you will spend most time in, the right thickness for it, and a fit that is snug without stopping you moving. Get those right and the cold stops being the thing that ends your swim. For a hand picking your first suit, pop into your nearest 53 Degrees North store and the team will help you find the fit. Order online for free Click & Collect, or free home delivery over €100 across Republic of Ireland and Northern Ireland, usually 1 to 2 working days with DPD. Browse the full wetsuit range when you are ready, and enjoy the water.