What Is Sizing Like at Athleta? An Honest Stylist's Fit Guide

Here’s the short answer: Athleta runs true to size for roughly nine out of ten pieces, so in most cases you can confidently buy your usual activewear size. The exception is the bottoms – leggings, joggers and some shorts tend to run a touch generous and stretch with wear, which is where a lot of women get caught out and end up swimming in fabric. Stick with me, because the difference between “true to size” and “true to size except” is exactly the kind of thing I wish someone had told me before my first order.

So, Does Athleta Actually Run True to Size?

For the most part, yes. Athleta is an American brand owned by Gap Inc., designed “by women for women,” and it’s a certified B Corp, so there’s a real considered approach to fit rather than just slapping numbers on a label. In my experience styling clients across a range of body shapes, the tops are the most reliable part of the range:

Tops, tees and long sleeves – dependably true to size. Take your normal size and you’ll be fine.
Leggings, joggers and bottoms – the forgiving ones. These have plenty of stretch and frequently run a little big, so if you’re between sizes, size down.
Sports bras and fitted tanks – the wildcard. If you’re fuller-busted, a few styles can pull tight across the chest, so check the individual product reviews rather than assuming.

I learned the leggings lesson the embarrassing way. I once ordered a pair of high-rise Athleta leggings in my “safe” size for a Pilates phase I was convinced would last (it lasted three weeks). They were lovely – and far too roomy at the waist, the dreaded gap-and-roll at the back. I sized down, the second pair fit like a glove, and I’ve never again bought their bottoms without sizing down when in doubt.

Understanding Athleta's Size Range

Athleta uses both letter sizing (XXS through to XXL) and an extended range up to 3X, alongside equivalent numeric sizing. What genuinely sets them apart is the length options – this is the bit I always flag to clients:

Petite – brilliant if you’re 5’3” and under and tired of hemming everything.
Regular – the standard fit for most heights.
Tall – properly long in the leg and body, not just an extra inch as an afterthought.

That three-length system is rarer than it should be, and it means you’re fitting your actual proportions rather than compromising. My advice: take your bust, waist and hip measurements with a soft tape before you order, check the chart on the specific product page (it varies slightly by style), and you’ll dodge most of the return faff. Their full-price pieces also carry a lifetime guarantee, so there’s real room to get the fit right.

The Catch for UK Shoppers

One honest heads-up, since most of you reading this are in the UK: Athleta’s American website doesn’t ship here directly. The good news is the brand is now stocked in the UK and Ireland through Next, thanks to the Gap-and-Next partnership, so you can shop a curated edit of leggings, sports bras, joggers and outerwear on next.co.uk with proper next-day delivery and free returns. The selection is smaller than the US offering, but the fit guidance above still holds.

Where Else to Shop: My Brand Recommendations

If you love the Athleta ethos – technical, flattering, designed for real movement – here’s where I’d point you across every budget.

High Street & Affordable

M&S – the Goodmove range is genuinely impressive value, with supportive leggings and sports bras that punch well above their price.
H&M – the Move activewear line is the budget hero for trend-led pieces you won’t mind replacing each season.
Superdry – sporty, casual and great for the off-duty athleisure look rather than hardcore training.

Premium

Sweaty Betty – the closest British equivalent to Athleta in spirit; beautifully engineered with a flattering, considered fit.
Lululemon – the benchmark for technical leggings; sizing runs the opposite way, so size down here too.
Gym Shark – performance-focused and sculpting, ideal if your priority is the gym floor.
Calvin Klein – my go-to for clean, minimalist sports bras and athleisure basics that double as loungewear.

Luxury & Designer

Tommy Hilfiger – the Sport line brings polished, preppy detailing to elevated activewear.

Two Independent Picks I Love

TALA – the sustainable British label founded by Grace Beverley; sculpting fabrics, sharp designs and a price point that undercuts the big names.
Girlfriend Collective – a brilliant under-the-radar brand making seriously inclusive, recycled-fabric leggings and bras with a cult following for good reason.

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