What Is Sizing Like at Eres? A Stylist's Honest Guide

By Ella Blake – Fashion Stylist | Tellar Fashion Hub – Always honest, unbiased & unsponsored

Eres runs small — sometimes frustratingly so — and if you're buying for the first time online, you need to know this before you spend. I remember the first time I ordered an Eres swimsuit thinking I'd simply use the French size equivalent of my usual UK 10. It arrived, I tried it on, and stood there looking like I was attempting to wear my younger sister's holiday purchase. Lesson one hundred in why French luxury sizing and UK sizing simply do not translate the way you'd hope. Consider this your shortcut to getting it right first time.

For those who haven't yet discovered the brand: Eres is a Parisian maison founded in 1968, now owned by Chanel, and absolutely revered among women who know their swimwear. The Peau Douce fabric — a buttery 77% polyamide, 23% elastane blend — is genuinely like nothing else. The cuts are minimalist, the colour palette is controlled and timeless, and once you've worn an Eres one-piece, it becomes very difficult to go back. The swimwear, lingerie, and occasional ready-to-wear pieces are investment purchases, which makes getting the sizing right all the more important.

How Eres Sizing Works

Eres uses French sizing throughout, ranging from FR 36 to FR 44. As a rough guide for UK shoppers:

FR 36 = UK 8
FR 38 = UK 10
FR 40 = UK 12
FR 42 = UK 14
FR 44 = UK 16

However — and this really matters — Eres consistently runs small within those French size brackets. The garments are cut with a close, second-skin fit in mind, particularly in swimwear and lingerie. There is very little built-in ease. The Peau Douce fabric does stretch, but nowhere near as much as cheaper jersey or lycra alternatives, so don't rely on stretch to make up the difference. If you are between sizes at all, size up. Eres themselves recommend this on their own website, specifically for anyone with a fuller bust or who prefers a looser fit — and honestly, in practice, it applies to most of us.

Swimwear Sizing: Tops and Bottoms Can Differ

Here's the bit that catches people out most with Eres: your top and bottom may well need to be different sizes — and that's completely normal, because Eres sells them as separates for exactly this reason. This is actually one of the brand's great strengths — but you need to know to use it.

Bikini tops — If you have a bigger bust, size up from your usual French equivalent without hesitation. Eres tops without underwire or padding are cut slim across the chest. A fuller cup can feel very restricted in your standard size. The brand's own advice echoes this: size up if you have a larger chest or simply want a more comfortable fit.
Bikini bottoms — These also run small, particularly across the hips. If you're curvier through the hips and thighs, sizing up here is often the right call. Don't be tempted to squeeze into your "correct" French size — the cut is unforgiving and the fabric, while stretchy, won't do all the heavy lifting.
One-pieces — These are where the sizing challenge can feel most acute, because you're working with both dimensions at once. If you carry more volume in the bust or hips, size up from your French equivalent. If you have a longer torso, be aware that some of the more minimal cuts can feel shorter than expected — Eres has some styles with extra stretch for this, so check the individual product notes.

Lingerie Sizing

Eres lingerie is something I find deeply underrated. It's the antithesis of heavily padded, over-engineered underwear — no boning, no thick foam cups, no scratchy lace that looks good in the drawer and nowhere else. Instead, it's sheer tulle, precision seaming, and a kind of quiet elegance that feels incredibly French. The bras are designed to flatter natural shapes, and they're genuinely beautiful pieces.

Sizing-wise: Eres lingerie also runs small to true, and the fit relies on your exact measurements more than most. Because there's no padding or thick lining to absorb a sizing error, a bra that's even slightly off will look and feel wrong. Use your bust and underbust measurements properly — not a rough estimate — and if in doubt, size up. The tulle-based styles in particular offer very little give, so precision really does matter here.

Ready-to-Wear, Kaftans and Bodysuits

Eres also produces seasonal ready-to-wear — think fluid kaftans, sheer beach dresses, soft bodysuits, and loungewear — and these carry the same swimwear DNA: clean lines, beautiful drape, minimal fuss. The bodysuits mirror the swimwear fit logic and should be sized up if you're curvy or broad-shouldered. The kaftans and dresses tend to be more forgiving by nature of their fluid construction, but if a style has any structure to it at all, apply the same rule and go up.

A Note on Fuller Figures and Bigger Busts

I want to address this directly, because I think it's genuinely useful. Eres, like many luxury French and Italian swimwear brands, designs for a narrower silhouette as its baseline. If you have a larger bust, fuller hips, or both, you may need to size up by one — occasionally two — sizes from what the French conversion chart tells you is "correct." This is not a reflection of anything other than the brand's cut. The good news is that Eres does sell tops and bottoms as separates, which makes it significantly more accommodating than brands that only offer complete sets. Mix your sizes. That's the whole point.

High Street and Premium Alternatives With the Same Aesthetic

If you love what Eres stands for — understated, minimal, beautifully made swimwear and lingerie — but want options with more forgiving sizing or a friendlier price point, these are the brands I'd steer you towards:

Calvin Klein — for clean, minimal swimwear and lingerie that shares a lot of the Eres aesthetic without the luxury price tag. The swimwear in particular is reliably well-cut and the sizing is far more straightforward for UK shoppers.
Sweaty Betty — brilliant if you want premium swimwear with real performance credentials. Their fabric technology is genuinely impressive and the sizing is consistent and more inclusive than most luxury swim brands.
Lululemon — for the activewear-adjacent swimwear look that has taken over every stylish poolside in recent years. Great hold, excellent sizing, and a clean, pared-back aesthetic that Eres fans will appreciate.
Tommy Hilfiger — a surprisingly strong option for classic, preppy swimwear that's consistently well-made. Their one-pieces in particular are flattering and true to size.
Mango — one of the best high street options for elevated-looking swimwear at genuinely accessible prices. Their minimal bikinis and swimsuits are excellent value and the sizing is reliable.
Urban Outfitters — worth a look for trend-led swimwear and lingerie with a more relaxed, youthful energy. The own-brand pieces in particular have improved enormously in recent years.
ASOS — an underestimated option for lingerie in particular. The own-label lingerie is well-made, the sizing is thorough and inclusive, and the range is broad enough that you'll almost always find what you're looking for.
Topshop — still a go-to for swimwear that punches well above its price point. The minimal styles especially are good alternatives when you love the Eres look but not the Eres outlay.

And two brilliant independent brands that deserve far more attention:

Heidi Klein — a British luxury swimwear label that is genuinely the closest thing the UK has to Eres. The quality, the cut, the colour palette — all exceptional. Importantly for UK shoppers, their sizing is also cleaner and more inclusive. If you haven't tried Heidi Klein, this is your moment.
Hunza G — the brand behind that gloriously distinctive crinkle fabric, beloved by everyone from Beyoncé to your coolest friend. The fabric is one-size in many styles and genuinely accommodates a wide range of bodies beautifully. Completely different in aesthetic to Eres, but equally considered and equally covetable.

Get Your Eres Size Right First Time — Free

When you're spending serious money on a luxury swimsuit or lingerie set, the last thing you want is to get the size wrong and deal with international returns. That's exactly why Tellar.co.uk exists. It's the UK's leading free sizing tool — match your real body measurements to Eres and 1,500+ other brands instantly, with zero guesswork.

Measure once — bust, waist, and hips (takes two minutes)
Use the Store Size Lookup tool to find your precise Eres size and your size in 1,500+ other brands instantly
Always free — no subscription, no download, no faff whatsoever

And make sure you explore the Tellar Fashion Hub — over 5,000 honest, unsponsored fashion posts written by our in-house stylists. No adverts, no paid-for recommendations. Just straight-talking advice from people who actually know their stuff.

Visit Tellar.co.uk Find My Eres Size →

The Final Word on Eres Sizing

Size up — that is the simplest and most reliable advice I can give you for Eres. Whether you're buying a bikini, a one-piece, or lingerie, default to going up from your French size equivalent if you're anywhere near a border between two sizes. Buy your tops and bottoms separately if they need to be different sizes — that's a feature, not a workaround. And use your actual measurements, not a guess, not a UK size translation, and not what you wore in a different brand last summer. Eres is precise, and precision rewards precision.

When it fits, though? There is genuinely nothing better. It's the kind of swimwear that makes you feel like you've got your life together even when you're standing barefoot on a beach with sand in your hair. Worth every penny — and every minute of sizing research.