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

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

Posse runs small — as an Australian brand, their sizing is cut for a slimmer, more petite frame, and most UK women should size up at least one, sometimes two sizes from their usual. If you're hovering between two sizes, go bigger every time.

I discovered Posse the hard way. I ordered a linen co-ord in my usual size, convinced by the gorgeous campaign imagery, and waited weeks for it to arrive from Australia only to find I couldn't get the trousers past my thighs. Brutal. But also, a completely avoidable situation had I known what I now know. So let me save you the heartbreak.

Who Is Posse?

If you haven't come across Posse yet, it's an Australian resort wear brand that has quietly become one of the most coveted labels in the "elevated holiday wardrobe" space. Think beautifully draped linen sets, silk-blend co-ords, and relaxed tailoring in muted, earthy tones — the kind of pieces that look effortless whether you're at a rooftop bar in Ibiza or a Sunday lunch in the Cotswolds.

Their aesthetic sits somewhere between Zimmermann and Faithfull the Brand — high quality, thoughtful construction, and pieces that photograph brilliantly. That's probably why their following exploded. But the brand is based in Byron Bay, Australia, and their sizing reflects that heritage.

Posse Sizing: What You Actually Need to Know

Posse uses Australian sizing, which on paper looks identical to UK sizing (both use the same numerical scale: 6, 8, 10, 12) — but the cut and construction are significantly more fitted. This isn't a loose, relaxed-fit brand despite the breezy aesthetic. Their garments are structured and close-cut through the bust and waist, which is where most UK women run into trouble.

Important caveat: these are approximate. Posse's fit varies by garment type — their trousers run the smallest, their tops are slightly more forgiving, and their dresses sit somewhere in between. Always check individual product measurements if they're available.

How Does Posse Fit Garment by Garment?

Tops & Shirts

Posse's linen and cotton shirts are cut slim through the shoulders and chest. If you have broader shoulders or a fuller bust, size up without hesitation. The poplin shirts in particular — lovely as they are — have very little ease built in. I'd say most UK women need to go up at least one full size here. A size 10 in the UK is very likely a size 12 in Posse, minimum.

Trousers & Shorts

This is where sizing up is most critical, and where I learned my lesson. Posse's tailored trousers have a high waist and a relatively narrow hip measurement. If you carry any weight on your hips or thighs, I'd recommend going up one to two sizes and using a belt if the waist ends up slightly loose. The fit through the leg is described as relaxed — but don't confuse that with generous. It's relaxed on a slender Australian frame.

Dresses

The wrap styles and slip dresses have a little more give and tend to be more forgiving than the tailored pieces. Still, size up one if you're between sizes — a wrap dress that pulls across the bust is never a good look. Do also check the length guidance; Posse's cuts are designed for a taller frame (around 5'8"), so petite women may find the midi and maxi lengths very long.

Co-ord Sets

My honest advice: size for your largest measurement and don't try to mix sizes within a set unless you're buying separates intentionally. Posse's co-ord sets are so beautifully matched in fabric and finish that breaking them up defeats the whole point — and they look incredible when worn as intended.

Fit Tips Before You Buy

Measure your bust, waist, and hips before ordering and compare against Posse's own size guide on their website — it's reasonably detailed and worth taking seriously.
Always size up if you're between sizes. The linen and poplin fabrics have minimal stretch, so there's no wiggle room.
Check the model measurements on the product page — Posse usually lists these, and comparing your own measurements to the model's gives you a much clearer picture of how a piece will actually sit.
Factor in returns. Shipping and returns from Australia are slow and can be costly. Getting your size right the first time is even more important here than with UK brands. Read their returns policy carefully before purchasing.

Alternatives to Posse: Brands Worth Knowing

I adore Posse, but the overseas shipping, the wait times, and the unforgiving sizing mean it doesn't suit everyone's lifestyle or budget. Here are the brands I recommend to clients who love the aesthetic but want something easier to buy and return in the UK:

High Street & Accessible Brands

Mango – Consistently brilliant for linen pieces and co-ords with a genuine Mediterranean resort sensibility. Their sizing is far more generous and consistent than Posse's. A genuine go-to for this aesthetic.
Zara – Their resort and holiday collections have improved dramatically. Look for the linen-blend blazers and wide-leg trousers in particular — they capture that Posse-adjacent mood well.
Cos – For the clean, minimalist architecture that Posse does so well, Cos is the obvious high street answer. Less resort, more considered — and brilliant quality for the price point.
Me&Em – A firm favourite for UK women who want elevated basics done properly. Their linen trousers and cotton poplin shirts are genuinely excellent, and the sizing is very true to a UK body.
Jigsaw – Never overlook Jigsaw for relaxed tailoring and quality fabric. Their holiday-adjacent pieces punch well above their price point and the fit is far less guesswork.
Whistles – Understated, well-cut, and perfect for the woman who wants to look effortlessly put together. Strong linen offering season after season.
Reiss – If you want the structured co-ord aesthetic without the Australian sizing drama, Reiss delivers it beautifully for the UK market. The tailoring is particularly strong.
Massimo Dutti – Criminally underrated for this resort-adjacent aesthetic. Spanish tailoring sensibility, beautiful natural fabrics, and a size range that accommodates UK bodies far more comfortably than Posse.

Independent Picks

Sézane – The French indie label with a cult following for exactly this kind of thoughtful, quality resort and everyday dressing. Their linen and silk pieces are gorgeous, the sizing is consistent, and the brand's ethos aligns beautifully with conscious shoppers.
Dôen – A California-based independent label with a romantic, sun-drenched aesthetic that genuinely rivals Posse's. Floral midi dresses, linen blouses, relaxed co-ords — all beautifully made and increasingly available with UK-friendly shipping and returns.

Premium Tier

Faithfull the Brand – If you love Posse, you'll love Faithfull. Australian heritage, very similar resort aesthetic, but better international sizing documentation and a stronger UK presence.
Vince – Effortless American luxury with a strong linen and silk offering. A wider, more accommodating fit and superb fabric quality.

Luxury & Designer

Zimmermann – The Australian luxury label that Posse's aesthetic clearly nods to. Expensive, yes — but the construction, the fabric, and the sheer wearability are genuinely exceptional.
Ulla Johnson – Romantic, artisanal, and beautifully considered. Worth every penny as a wardrobe investment, particularly the linen and broderie pieces.

Never Guess Your Size Again — Use Tellar

Brands like Posse are exactly why Tellar.co.uk exists. When you're ordering from an overseas brand with unfamiliar sizing conventions — and paying for international shipping on top of it — getting it wrong is expensive and deeply frustrating. Tellar's free sizing tool matches your measurements to over 1,500 brands instantly. No downloads. No paywall. No faff.

Step 1: Measure once — just your bust, waist, and hips (or use an existing brand size you know fits well).
Step 2: Use the Store Size Lookup tool — get your precise size in any brand, from Posse to Zara to Reiss and 1,500+ more.
Step 3: Shop with confidence. Always free. Works in-browser. No account needed.

And for more style guidance, the Tellar Fashion Hub is a library of honest, unsponsored posts from our team of stylists — covering everything from the best jean trends to detailed brand sizing breakdowns. All free. Always independent.

Visit Tellar.co.uk | Store Size Lookup Tool