Tech Suit Size Guide: How Tight Should a Tech Suit Be?

Sizing is where most tech suit purchases go wrong. Get it right and the suit works with you. Get it wrong and you have either thrown away the compression you paid for or spent 30 painful minutes squeezing into something a size too small.

How Tight Should a Tech Suit Feel?

A tech suit should feel firm everywhere and painful nowhere. You want clear pressure through the hips, glutes and thighs, a waistband that stays put when you streamline, and no pinching behind the knees or at the waist. If you cannot get it past mid thigh after a few minutes of working it up, it is too small. If it wrinkles or gapes anywhere once on, it is too big.

One size down is not one step faster. Modern flagship fabrics are engineered to compress at their intended size. With suits like the Arena Primo, the compression readings are the same one size up, it just takes minutes rather than half an hour to put on.

Brand by Brand Sizing Notes

Mizuno: runs compressive by design. The GX Sonic range is meant to feel mechanical, especially the sprint cuts. If you sit between sizes, most swimmers should go up. My guide to the GX Sonic Royal range covers which cut suits which events.

Arena: the Primo is unusually sensitive to size choice because its hyperforce fabric holds compression when stretched. One down is painful, one up loses nothing. Full details in my Arena Primo review.

Speedo: the most conventional fit of the big brands. The Pure Valor 2.0 comes in two waist heights, which solves most fit complaints on its own. See my Pure Valor 2.0 review.

TYR: the Venzo is built for swimmers who want to feel locked in, so do not panic if it feels extreme on first wear. My TYR Venzo review explains what to expect.

Jammer vs Kneeskin Fit

The rules are the same for both: firm compression, nothing digging in, full range of motion at the shoulders and knees. Kneeskins add strap fit to the equation. Straps should sit flat without cutting in, and you should be able to streamline without the suit pulling at the shoulders.

Practical Tips Before You Buy

Order from a retailer with a good returns policy and try the suit on at home, dry, well before race day. Put it on carefully, sit in a streamline, do a few squats. If you are between sizes, order both and return one. A tech suit is a big investment, so treat the fitting like part of the purchase.

Not sure which suit to size up in the first place? My TOP 10 tech suits for 2026 ranks every flagship, or take the free Tech Suit Finder quiz for three personalised recommendations.

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