Coast Sizing Guide: Does It Run Big or Small? What Every Shopper Needs to Know

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

Coast runs small to true-to-size — and if you're a fuller bust or carry any weight around your middle, you'll very likely need to size up. I say this from experience: I've helped dress a lot of women for weddings, race days, and black-tie events in Coast over the years, and the number one mistake I see is women ordering their usual size and finding themselves in a zip-tugging standoff in the fitting room. Coast makes some genuinely beautiful occasionwear, but it's cut with a particular body type in mind — and understanding that before you shop will save you a lot of frustration (and returns).

A Bit About Coast

Coast is one of Britain's most recognisable occasionwear brands. It's been a go-to for weddings, parties, and formal events for years — and rightly so. The silhouettes are polished, the fabrics feel considered, and there's a real elegance to the styling that's hard to find at this price point. The brand relaunched as a digital-first label and now sits primarily online, which actually makes getting the sizing right even more important — there's no nipping into a branch to try before you buy.

Their sweet spot is structured, tailored dresses, jumpsuits, and formalwear. It's not a brand you pop into for a casual Saturday outfit — it's very much built around occasion dressing, and the cuts reflect that. Which brings us to the elephant in the room.

So, Does Coast Run Small?

Yes — particularly in structured pieces. Coast builds a lot of its dresses and eveningwear with defined, fitted bodices, structured waistbands, and close-to-the-body silhouettes. This is what makes the clothes look so elegant on the hanger and on the model. But it also means there's very little ease built in, especially through the bust and waist.

The general rule I give clients is this: if you're between sizes, always go up at Coast. And if you're a fuller bust, go up regardless of where you sit size-wise. I've had clients who are a comfortable size 12 everywhere else needing a 14 at Coast — particularly for anything with a structured bodice or zip fastening. That's not a sizing failure, it's just how the brand cuts its clothes.

Fit by Garment Type

Coast isn't one-size-fits-all in its fit quirks, so it's worth breaking it down:

Occasion dresses (woven & satin fabrics): These are where sizing is most critical. Structured bodices, defined waistlines, and non-stretch fabrics leave very little room for error. Size up if you have any doubt — especially for off-the-shoulder or strapless styles, which are notorious for being snug through the bust.
Jersey & knit dresses: Much more forgiving. The stretch compensates for a lot, and here you can often go true to size with confidence.
Jumpsuits: These are genuinely tricky. The torso is cut narrow, and if you're long in the body or curvy through the hips, the fit can feel very restricted. I'd always advise sizing up in jumpsuits — petite sizing is worth considering too if you're 5'4" or under, as standard lengths can be very long in the leg.
Tops & blouses: Generally more true to size, and these are where the Coast fit actually works well for most body types. Stick to your usual size here.
Blazers & coats: Designed with some ease for layering, so these tend to behave more consistently. True to size usually works well.

💡 Stylist tip: Pay close attention to the fabric content before you order. Anything listed as 100% woven polyester, satin, or structured crepe is going to have zero give — size up. If there's elastane in the mix, you've got a bit more room for manoeuvre. Also check whether there's a zip or button fastening — zips at the back are the most unforgiving if you're between sizes.

The Body Shape Factor

I'll be honest about something that doesn't get said enough: Coast's cutting has historically worked best for a particular frame — proportionate bust and hips, defined waist, and fairly standard height. If that's you, Coast fits beautifully and you can likely shop your usual size with confidence. But if you carry more weight through the bust, hips, or middle, the structured nature of the garments can feel really quite restrictive — even in a size up. This isn't a criticism of the brand, it's just useful information to have going in.

Real customer feedback tells the same story consistently: if you're an hourglass shape with a fuller bust, expect to size up. If you're more straight up and down and lean, Coast often fits exactly as expected. The brand has improved its inclusivity over recent years, but the fitted occasionwear remains cut fairly slim through the body.

Petite Shoppers

Good news here — Coast actually does petite sizing reasonably well. If you're under 5'4", the petite range is genuinely worth looking at, particularly for maxi and midi dresses and jumpsuits where standard lengths can be overwhelming. The proportions are adjusted throughout, not just hemmed shorter, which makes a real difference to how the finished look lands.

Love the Coast Look? These Brands Are Worth Knowing

If Coast doesn't quite work for your shape — or your budget — here are some excellent occasionwear alternatives across different price points, all worth bookmarking:

Phase Eight — Consistently one of the best occasionwear brands on the high street for women who want elegance without the sizing anxiety. Cuts are generally more generous and flattering across a wider range of body shapes. A brilliant Coast alternative.
Hobbs — Sophisticated British tailoring with reliable, consistent sizing. The occasionwear range is beautifully cut and tends to be kinder to fuller figures than Coast. Great for weddings and smart events.
Reiss — If you want something sleeker and more fashion-forward, Reiss delivers polished occasion dressing with excellent fabric quality. Sizing is fairly consistent and generally true to size.
Ted Baker — Known for beautifully detailed, feminine occasion pieces. The sizing runs slightly generous compared to Coast, making it a good shout if you've found Coast too snug in the past.
LK Bennett — An absolute staple for smart British occasionwear. Kate Middleton's go-to for a reason — the fit is elegant, the sizing is generally reliable, and the quality is excellent for the price point.
Monsoon — Brilliant for occasion dressing with a more bohemian, relaxed edge. The sizing is generally more generous than Coast, and the prints and embellishment make for genuinely stunning event outfits.
French Connection — For something a little more contemporary and pared-back. Good quality occasion pieces at a mid-market price point, and the sizing tends to be true to size or slightly generous.
Mango — Increasingly impressive for occasion dressing, especially in the premium line. Great fabric quality, lovely silhouettes, and sizing that tends to be more consistent and accommodating than Coast.

Two independent brands I'd genuinely recommend:

Needle & Thread — If you want something genuinely special for a wedding or black-tie event, Needle & Thread is the answer. The embellishment and craftsmanship is extraordinary, and the sizing (UK 6–18) is clear and consistent. It's a splurge, but one you won't regret.
Ghost London — A cult British label that's been making beautiful, floaty, occasion-ready dresses for decades. The bias-cut satin pieces are iconic, the sizing is generous and forgiving, and there's a timelessness to Ghost that fast fashion simply can't replicate.

Getting Coast Right First Time — Here's How

Given how specifically Coast cuts its occasionwear, getting your size wrong is a real risk — especially when you're shopping for something important like a wedding guest outfit or a work event. This is exactly where Tellar.co.uk earns its keep.

Tellar is the UK's leading free sizing tool — it matches your actual body measurements to real fit data from 1,500+ brands, including Coast. No vague size guides, no crossed fingers, no expensive returns.

Measure once — just your bust, waist, and hips. That's all it takes to build your profile.
Use the Tellar Store Size Lookup tool to instantly find your correct size in Coast — and hundreds of other brands, from Phase Eight to Reiss.
Always free — no subscriptions, no downloads, no faff. Works straight in your browser, right now.

And while you're there, explore the Tellar Fashion Hub — thousands of honest, stylist-written posts covering everything from brand sizing breakdowns to trend guides and occasion dressing advice. No ads, no sponsored content, no brand influence. Just real, useful fashion information, completely free.

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