Brief, Jammer or Shorts: What to Actually Wear for Lap Swimming

Swim brief, jammer or board shorts for lap swimming: what each one does to your drag, your kick and your kit bag, and which of them belongs in a pool.

By Keith · 12 June 2026 · 3 min read

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Competitive swimmers own a thing called a drag suit. It is a loose, baggy extra suit worn over the normal one during training, bought deliberately, for the express purpose of making swimming harder. It holds water and creates resistance so that race day feels easy by comparison, and it settles most of this argument before it starts.

A drag suit looks almost exactly like a pair of board shorts.

If you swim lengths in shorts, you are doing resistance training you did not sign up for, paid for in shoulder fatigue and lengths not completed. So let us go through the three options honestly, because two of them are proper equipment and one of them is beachwear that wandered indoors.

The brief

The swim brief is the minimum viable swimsuit and that is precisely its engineering. Almost no fabric in the water, so almost no drag. Nothing across the thigh, so the hips and legs move through their full range on every kick and turn. It dries in minutes rather than hours, which matters more than people expect when the alternative is a wet lump in your bag all afternoon. It packs down to the size of a pair of socks, so it lives permanently in the bottom of a rucksack for unplanned swims. And it is the cheapest option in the shop, usually by half. classic swim brief · chlorine-resistant polyester swim brief

For lane swimming, the brief is the default. Not the brave choice, not the retro choice. The one built for the job. Your First Speedo: The Complete Buying Guide

The jammer

The jammer covers waist to mid-thigh or knee and is what most club and elite swimmers race in, because since 2010 it is the largest suit the rules allow a man to wear. Speed On In Your Speedos: The Sydney Knitting Mill That Named the Swim Brief

It has real advantages. Compression on the thigh feels supportive over long sets. The extra coverage is welcome in a cold pool or an outdoor lido in April. Some swimmers simply prefer the security of it, and a swimmer who is comfortable swims more, which beats every other consideration on this page. Once the water is cold enough for neoprene the question changes shape entirely, because the layer underneath either helps the suit work or fights it. What to Wear Under a Wetsuit

The catches are cost and care. Jammers are two or three times the price of a brief, they take much longer to dry, and a cheap one will chafe the inner thigh in a way a brief physically cannot. Buy a good one or do not bother. training jammer

The shorts

Board shorts, swim shorts and anything with a pocket belong at a barbecue, on a lounger or in the sea for twenty minutes of not really swimming. They are perfectly good clothes. They are simply not swimming equipment, and every length you swim in them is slower and harder than it needed to be. Many pools with any competitive tradition ban them outright, and every pool in France effectively does. The French Pool Rule: Where Swim Briefs Are the Law

Choosing, in one paragraph

Swimming lengths regularly, indoors, in a heated pool: brief. Racing, or swimming long sessions in cold water: jammer, or a brief with a decent second skin if you feel the cold. Open water and sea swimming: brief for most, jammer if the temperature bites, and the same answer either way once you are out and changing under a robe on a car park in November. The Sea Swimmer's Case for the Swim Brief

Whichever you choose, buy the fabric that survives chlorine. Standard elastane blends sag and go see-through after a few months of hard pool use, while polyester and PBT training fabrics last for years of it. The maths works out the same way it does with underwear: the cheap thing bought twice a year is the expensive option. Buy It Once: The Durability Guide to Briefs That Last Years

The real reason people swim in shorts

It is not comfort and it is certainly not performance. It is the walk from the changing room to the water, roughly eleven seconds of feeling looked at, and it costs some men years of worse swimming. The fix is not a bigger garment. The Locker Room Question: Getting Over the Fear of Being Seen in Briefs

Swimmers buy drag on purpose. Do not wear it by accident.

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