What Is Sizing Like at Billabong?

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

Billabong sizing generally runs true to size, but there are a few quirks worth knowing before you order — particularly around swimwear, denim, and the brand's Australian sizing roots. Let me break it all down for you honestly, because I've been there, staring at an unfamiliar size label on a lovely pair of boardshorts wondering what on earth I'm supposed to do with it.

A Quick Word on Billabong as a Brand

Billabong was born in 1973 on Australia's Gold Coast — and that heritage genuinely matters when it comes to understanding how they size. The brand was built around surfing, beach life, and that laid-back Aussie coastal aesthetic. Today, it's grown into a full surf-lifestyle label covering everything from boardshorts and bikinis to wetsuits, casual dresses, and denim. It's well-loved by surfers and beach holiday shoppers alike, and it sits at a mid-market price point — not cheap high street, but not eye-wateringly expensive either.

The range is actually broader than a lot of people realise. Yes, you'll find the classic bikinis and board shorts, but there are also really lovely maxi dresses, easy cotton shirts, hoodies, and casual separates that work well away from the beach. I wore a Billabong wrap dress to a friend's birthday drinks last summer and got more compliments on it than anything I've worn in ages. So it's worth knowing how to get the fit right.

Does Billabong Run True to Size?

For most womenswear — tops, dresses, casual pieces — yes, Billabong runs pretty true to size. If you're normally a UK 10–12, you'll likely be comfortable in a Small or Medium. The fit is relaxed and slightly athletic in style, which works well for most body shapes.

A few things worth flagging though:

Swimwear tops can run slightly snug in the band — if you're fuller in the bust, it's worth sizing up on bikini tops specifically. A friend of mine who wears a 34D has learned to go one size up on Billabong swim tops to get the coverage and comfort she needs.
Cheeky-cut bikini bottoms tend to come up small. If you like more coverage, or you're between sizes, size up on the bottoms without hesitation.
Denim aligns with standard US sizing, so look at the waist measurement rather than the letter size to find your fit. Billabong denim tends to be cut with a relaxed, coastal silhouette — not particularly fitted through the thigh.
Wetsuits run true to size but have a slightly wider cut through the panels, which is actually brilliant if you've got an athletic build or a bit of curve. Slimmer builds may want to size down on wetsuits.
Oversized styles — hoodies, crewnecks, baggy shirts — are designed to be roomy. If you want the proper streetwear-draped look, stay true to size. If you want a more fitted look, size down.

UK vs. Billabong Sizing — What You Need to Know

Because Billabong is an Australian brand, they use Australian sizing, which is very closely aligned with UK sizing — in most cases they match up directly. A UK 10 is broadly equivalent to an AU 10 in Billabong clothing, so you won't need to do complicated mental arithmetic at checkout, which is always a relief.

The place where it gets a little confusing is swimwear, where Billabong often uses a blend of XS–XL letter sizing and US numeric sizing simultaneously. My honest advice? Use your measurements rather than your usual letter size when shopping swimwear. The Tellar tool is genuinely brilliant for this — more on that below.

Billabong Swimwear: Getting the Fit Right

Swimwear sizing is famously stressful at the best of times, and Billabong is no exception. The good news is that the brand actually offers a decent fit guide on their site, and they do a few things well:

They offer mix-and-match separates, so you can size your top and bottom independently — a genuine win if you're not a standard proportioned size.
One-piece swimsuits are cut with torso length in mind. If you're petite (under 5'3"), look for their shorter-torso options; if you're longer in the body, a standard length will work perfectly.
Their UPF 50+ fabrics hold up really well to salt and sun, and the quality of the swimwear is solid for the price point.

The Style: Who Is Billabong For?

Honestly? It's for anyone who loves that relaxed surf-coastal-summer aesthetic. You don't have to surf. I certainly don't — my board sport prowess extends to a very wobbly attempt at paddleboarding once in Cornwall — but I absolutely love the Billabong vibe for beach holidays, summer festivals, and casual warm-weather dressing. The colour palettes lean into earthy tones, ocean blues, and sun-faded prints, and the fabrics are breezy and light. It's a very easy brand to shop.

It also sits nicely alongside brands you might already wear, so if you're thinking about what else to consider for that coastal-cool wardrobe, here are my honest recommendations by tier.

High Street Alternatives to Billabong

If Billabong's sizing isn't quite working for you, or you want to explore similar vibes at comparable or lower price points, these are the brands I'd genuinely recommend:

Hollister — the closest vibe to Billabong on the high street. California-inspired, relaxed cuts, good quality basics and swim. Their sizing runs small so go up one if in doubt.
Abercrombie & Fitch — massively improved in recent years. Their linen shirts, casual dresses, and swim separates are excellent, and sizing is more consistent than it used to be. A big yes from me.
Superdry — great for the coastal-meets-sport aesthetic, particularly hoodies, lightweight jackets, and casual separates. Runs slightly large in some pieces.
ASOS — brilliant for sourcing Billabong-adjacent swim and casual pieces with a huge range of sizes and body types covered.
Urban Outfitters — ideal for the boho-beach crossover look. Lovely dresses, oversized tees, and easy separates that sit in the same aesthetic family.
Fat Face — particularly good for the UK coastal customer who wants that outdoorsy, beach-holiday feel with a slightly more grown-up edge. Sizing is reliable and true to size.
Seasalt Cornwall — if Billabong's surf-cool aesthetic isn't quite your thing but you love the seaside feel, Seasalt is a wonderful British alternative. Honest sizing, great fabrics, and genuinely lovely prints.
Levi's — for denim that works alongside your Billabong swim and casual pieces, Levi's is the obvious and correct answer. Size by waist measurement as you would with Billabong denim.

Premium Picks

Lululemon — not strictly a surf brand, but for the active-beach crossover customer their swim and casual pieces are outstanding quality. Sizing is consistent and runs true.
Sweaty Betty — brilliant if you want technical fabrics that handle both sport and beach life. Their swim range has improved enormously and is worth a look.
Barbour — for coastal dressing that extends into the cooler months, Barbour is unbeatable. Their lightweight jackets and shirts layer beautifully over surf-brand separates.

Two Independent Brands Worth Knowing

Finisterre — a genuinely brilliant British surf and outdoor brand based in Cornwall. Ethically made, sustainably focused, and the swimwear and wetsuits are exceptional. If you want the Billabong ethos but with a more conscious, UK-rooted brand behind it, Finisterre is the one. Sizing is true to UK sizing throughout.
Passenger Clothing — another UK independent worth knowing. They make beautiful organic-cotton casual wear, easy dresses, and outdoor pieces with a real outdoor-coastal feel. Relaxed fits, honest sizing, and genuinely lovely fabrics. A bit of a hidden gem.

Never Guess Your Size in Billabong Again — Use Tellar

Billabong's mix of letter sizes, US numeric sizing, and Australian roots can make shopping online a bit of a lottery. That's exactly why Tellar.co.uk exists.

Tellar is the UK's leading clothing sizing tool — it matches your exact body measurements to over 1,500 brands instantly. No more guessing, no more returns, no more sizing chart confusion.

Measure once — bust, waist, hips, or use your size in a brand you already know.
Use the Store Size Lookup tool to get your precise size in Billabong and hundreds of other brands.
Completely free. No downloads. Works in-browser, right now.
Plus explore the Tellar Fashion Hub — a free library of honest, unbiased style advice from our team of stylists.

Find Your Billabong Size → Tellar