On May 12, 2025, the municipality of Arbois adopted an internal regulation for its swimming pool that prohibits “swim shorts” and only accepts swim briefs and trunks for men. In Isère, the Porte de l’Isère urban community accepts boxers but refuses “long boxers.”
The swim boxer thus sits right on the line. And if you also wear it for snorkeling or under a wetsuit, other criteria come into play: resistance to chlorine and salt, drying, seams, and UV protection.
We go over these criteria one by one, with dated rules and standards that really exist.
Is the swim boxer accepted in French swimming pools?
Often yes, but not everywhere. To our knowledge, no national text sets the cut of the swimsuit. The Public Health Code regulates hygiene and water quality, and each operator writes their dress code in their internal regulations. The short, fitted boxer is allowed in many public pools. Loose swim shorts, on the other hand, were rejected in all the regulations we consulted in October 2026.
The recurring criterion everywhere is a garment reserved for swimming.
The ARS Provence-Alpes-Côte d’Azur summarizes the expectation in a guide published in April 2017, where the bather commits to coming with a “clean and swimming-appropriate” swimsuit, to shower with soap, and to use the footbath. Shorts worn on the street or on the sand bring sand, sweat, and cream residues into the pool. Local regulations express this idea each in their own way. The CAPI’s says it wants to “limit water contamination.” The Guingamp pool’s regulation, dated October 6, 2023, excludes swim shorts and covering outfits.
However, the word “boxer” does not mean the same thing from one manufacturer to another. A model that reaches mid-thigh can be classified as a “long boxer.” Before a session in a pool you don’t know, read the article on dress code in its regulation, often posted at reception or published on the town hall or intercommunal website.
Which material holds up best against chlorine and salt?
Polyamide and polyester are the two common bases. Polyester, especially in its PBT version, generally retains its shape better in chlorinated water. Elastane provides elasticity, but it is the fiber that chlorine wears out the fastest, and the previous version of this article was wrong to present it as chlorine-resistant. For the pool, therefore, check the elastane content on the label.
Salt damages the fiber less than chlorine, but when drying it crystallizes in the mesh and makes the fabric rough against the skin. Sand gets embedded in the lining. Turn it inside out to empty it. Rinsing with fresh water after each outing limits damage, and drying in the shade is better than using a dryer, because heat also weakens elastane. Thus, a simple and well-rinsed boxer often ages better than a more expensive model forgotten for three days in a damp bag.
A label stating “chlorine resistant” without detailed composition does not prove much.
Can you wear a swim boxer under a wetsuit?
Yes, it is a common outfit under a wetsuit. Choose a short, fitted model with flat seams, no pockets or large drawstring knots. Under neoprene, anything that creates thickness stays pressed against the skin throughout the dive and can end up irritating, especially when dives follow one another over a week.
The drawstring deserves a look. A large knot gets crushed on the belly by the jacket strap or weight belt. A pocket with Velcro has the same effect on the hip. But the point that most often ruins a diving day is drying. A boxer still wet when putting on the suit for the second dive stays cold against the skin, and you will feel it more in 20 °C water than during diving holidays in Egypt in the middle of summer.
So plan two boxers and alternate them.
For the rest of the bag, the equipment section reviews mask, regulator, and accessories. The swimsuit remains the cheapest piece of the lot, yet it is the only one you wear at every immersion, from training pool to boat.
Does a swim boxer protect from the sun while snorkeling?
A little, and only where it covers. The fabric blocks part of the UV rays, but a boxer leaves the back, shoulders, and back of the thighs bare, that is, the most exposed areas when you float face down on one of the best snorkeling spots in France. A UPF rating on the label only applies to the covered surface.
The UPF rating follows standards. The Australian and New Zealand standard AS/NZS 4399:2017, applied by the ARPANSA agency, classifies fabrics into three categories: minimum (UPF 15), good (UPF 30), and excellent (UPF 50 and 50+). In Europe, the EN 13758-2 standard reserves the UV protection claim for garments that reach at least UPF 40 with less than 5% UVA transmission. However, ARPANSA specifies that protection can decrease if the fabric is wet, stretched, worn, or exposed for a long time to pool products. A swim boxer often ticks several of these boxes.
For the upper body, a long-sleeved UV-protection top will always do more than the best boxer (that’s our opinion, and it doesn’t cost much to follow).
And if you add sunscreen, choose it also thinking about the reefs. We summarized what we know about sunscreen and marine environments.
What size and cut should you choose?
Start with your waist measurement, taken with a tape measure, and compare it to the manufacturer’s size guide. The letters S, M, or L do not correspond to the same measurements from one brand to another. For the pool as well as for the wetsuit, aim for a boxer that stays up on the waist without tightening, with a leg that stops well above mid-thigh.
The previous version of this article associated S-M with slim figures, L with average builds, and XL with larger people. This chart was not based on any measurement, so we removed it, and did the same with color advice according to complexion, which was only a matter of taste. Choose what you like. However, a light and very thin fabric can become a bit transparent once wet, which deserves a test under the shower before departure. The test takes a minute.
Regarding manufacturing, brands like Le Slip Français sell swim boxers in polyamide presented as made in France. Origin is a personal criterion; it’s up to you to decide if it matters.
In short, a poorly chosen boxer mainly costs you comfort, with chafing under the wetsuit and cold fabric between dives.
FAQ
Are swim shorts banned by law in swimming pools?
To our knowledge, no national text sets the cut of the swimsuit. The rule comes from each pool’s internal regulations, and those we consulted in October 2026 all refused loose swim shorts. The short boxer is often accepted, with exceptions for long models.
Which material to choose for a boxer worn in chlorinated pools?
Polyester, especially PBT, generally holds up better to chlorine than polyamide. The lower the elastane content, the less the fabric stretches quickly. Rinse it with fresh water after each session.
Do you need a special boxer to wear under a wetsuit?
No. A short, fitted swim boxer with flat seams and no large drawstring knot is suitable under a wetsuit. Having a second dry boxer for the next dive changes comfort more than the model itself.
Is a UPF 50+ boxer enough against the sun while snorkeling?
It only protects the area it covers. ARPANSA indicates that fabric protection can decrease when wet, stretched, or worn by pool products. For the back and shoulders, a long-sleeved UV top does more.
Sources
- Your pool is also mine (ARS Provence-Alpes-Côte d’Azur, 2017)
- Information for New Zealand consumers and manufacturers (AS/NZS 4399:2017) (ARPANSA, 2017)
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