The Tween Bikini Size Guide (Sizes 8–14): How to Get the Fit Right First Time

Getting swimwear sizing right for a tween is trickier than you'd think. Your daughter isn't a little kid anymore, but she's not quite a teenager yet. She's somewhere wonderfully in-between, which makes sizing a real challenge.

Standard children's sizing doesn't fit her anymore. Women's sizing swamps her. Finding a tween bikini size guide that actually makes sense? That's exactly why you're reading this.

Here's what makes it complicated: there's no universal tween bikini sizing standard across brands. Two girls aged 12 can have completely different measurements. One might be taller and leaner. Another might be shorter with more curves. They're both perfectly normal. They're both tweens. And they both need swimwear that actually fits their bodies right now.

This guide exists to solve that problem. We'll walk you through measuring your daughter accurately, reading a size chart with confidence, and avoiding the most common sizing mistakes parents make when buying tween swimwear online. By the end, you'll know exactly which size to order the first time.

Why Tween Sizing Is Different

Tweens are in that unique window where their bodies are changing rapidly. Growth spurts happen overnight. Body composition shifts. What fits one season might not fit the next.

But right now, this summer, you need something that works perfectly.

Sorbae was designed with this reality in mind. Our range covers sizes 8–14 and was built specifically for tweens, not adapted from a children's line or scaled down from juniors. Each size is engineered for where a tween's body typically sits at that age, accounting for shoulder width, torso length, hip development, and all the subtle differences that make tweens, well, tweens.

The result? A tween bikini size guide and fit that actually works, because we started with tweens' measurements, not assumptions about what "should" fit at each age.

How to Measure Your Daughter for Swimwear

Before you even look at a size chart, you need accurate measurements. This is the foundation of everything.

Use a soft measuring tape (the kind tailors use). Keep the tape snug but not tight. Measure over regular clothing, not through a jumper.

Step 1: Bust Measurement

Measure around the fullest part of your daughter's chest, keeping the tape parallel to the ground. The tape should sit flat and level all the way around. Write this number down.

Step 2: Waist Measurement

Find the natural waistline, usually just above the belly button where the body bends when she leans to one side. Measure around this point, keeping the tape snug but not tight. The tape should sit level and flat.

Step 3: Hip Measurement

Measure around the fullest part of the hips, typically about 20 centimetres below the waist. Keep the tape parallel to the ground, just as you did for the bust.

Now you have three key measurements. These are the numbers you'll use to find the right size in the Sorbae size chart.

Understanding the Sorbae Size Chart

Here's where the tween bikini size guide really comes into play. Sorbae's sizing runs as follows:

• Size 8: Designed for tweens aged 7–9, typically with a bust of 66–71cm, waist 61–66cm, hips 71–76cm.

• Size 10: Designed for tweens aged 9–11, typically with a bust of 74–79cm, waist 69–74cm, hips 79–84cm.

• Size 12: Designed for tweens aged 11–13, typically with a bust of 81–86cm, waist 76–81cm, hips 86–91cm.

• Size 14: Designed for tweens aged 13+, typically with a bust of 89–94cm, waist 84–89cm, hips 94–99cm.

The key word here is "typically." Age is a guide, not a guarantee. Your 10-year-old might measure into a Size 12. Your 12-year-old might be a solid Size 10. That's completely normal. Always go by measurements, not age.

What If She's Between Sizes?

This happens all the time. Maybe her bust measures Size 12, but her hips are closer to Size 10. Now what?

First, prioritise the bust measurement. The bust is the hardest thing to get right, and a slightly loose hip is far more comfortable than a tight chest. If her measurements genuinely sit between two sizes, size up.

A slightly roomy fit around the waist is manageable. A tight bikini top that restricts breathing is not.

Second, remember that tweens wear their swimwear differently now than they did at 6 or 7. Fit can be a little more relaxed and still look great. You're not looking for a skin-tight fit. You're looking for comfort and confidence.

Common Sizing Mistakes Parents Make

Mistake 1: Buying by Age Instead of Measurement

"She's 11, so she should be a Size 11." Nope. Two 11-year-olds can have vastly different measurements. Always measure first. Ignore the birthday.

Mistake 2: Sizing Down to "Make It Last Longer"

A tight bikini doesn't last longer. It just makes your daughter uncomfortable all summer. When she grows, she grows. Size appropriately now. Worry about next season when it comes.

Mistake 3: Forgetting About Arm Holes and Leg Openings

The bust and hip measurements matter, but so do arm holes and leg openings. These aren't always listed on a standard size chart, but they matter for comfort. If your daughter tends toward a curvier build or has broader shoulders, pay attention to these details when you're reading product reviews.

Mistake 4: Not Accounting for Different Fabric Stretch

Different swimwear fabrics have different amounts of stretch. Sorbae's hand-beaded styles have a specific stretch profile. Always check the product description for fabric details before ordering.

Mistake 5: Ignoring the Returns Policy

Even with perfect measurements, sometimes a tween tries something on and the fit just doesn't feel right to her. This is why Sorbae offers 30-day returns with a sanitary seal intact. Order with confidence knowing you can easily exchange if needed.

How to Measure for Specific Sorbae Styles

Different bikini styles can fit slightly differently. A high-waist brief might sit differently on the body than a classic brief.

When you're shopping our collection, whether you're drawn to Hibiscus Crush, Limoncello Love, or Sea-foam Kiss, check the individual product description for any style-specific fit notes.

For example, some of our hand-beaded styles have a specific coverage and fit that might run slightly different from a plain style. Always read the product page. If you're unsure, that's exactly what our returns policy is for.

Pro Tips for Online Ordering

• Take a photo of your measurements: Screenshot the size chart and your daughter's measurements so you have them all in one place when you're ordering.

• Read reviews from other parents: Real customer reviews often mention whether a style runs large, small, or true to size. These are goldmines for sizing confidence.

• Remember the free swim bag: Every Sorbae order comes with a free Bikini Swim Bag. One less thing to buy, and your daughter will love having a dedicated bag for her new suit.

• Allow time for postage: Allow 3–5 days for postage, so order with enough time before summer holidays or family trips. There's no rush, but there's also no need to panic. We've got you covered.

• Take advantage of the Launch Special: Right now, it's Buy 2 Get 1 Free on the full collection, plus the free swim bag with every order. If your daughter has summer plans and needs multiple suits, this is the time to stock up.

Why Sorbae Sizes Matter

Here's something important: not every tween swimwear brand thinks about Australian summers. Sorbae does.

Designed on the Sunshine Coast for Australian kids, this collection was built with your daughter's body in mind, at her age, in her season.

Each size is measured and mapped carefully. Each style is tested for fit, comfort, and durability through an Australian summer. And each suit arrives with hand-beaded charm detail that your daughter will actually want to wear.

When you're working through a tween bikini size guide and comparing options, remember you're not just buying a suit. You're buying confidence. You're buying fit that's been thought through. And you're buying Australian-designed quality that's made to last.

Frequently Asked Questions

What if my daughter's measurements fall between two sizes?

Size up. Prioritise the bust measurement first. That's the hardest part to adjust. A slightly roomy fit at the waist is far more comfortable than a tight chest, especially as tweens are still developing.

Does Sorbae run large or small?

Sorbae runs true to size when you follow the measurement guide. The best way to ensure the right fit is to measure your daughter accurately using the three-step process: bust, waist, and hips. Always go by measurement, not age.

My daughter grew a lot this year. Should I order a Size 12 instead of Size 10?

Measure her now. If her current measurements sit in Size 12, order Size 12. If they're still in Size 10 with room to grow, stick with Size 10. A well-fitting suit now is better than over-sizing "for later."

Can I exchange if the size doesn't fit?

Yes. Sorbae offers 30-day returns and exchanges with the sanitary seal intact. If your daughter tries it on and the fit isn't right, you can easily swap it for a different size.

How long does postage take?

Allow 3–5 days for postage. Sorbae offers free shipping Australia-wide and internationally, so you're covered wherever you are.

Are there size-specific details I should know (like arm holes or leg openings)?

Different Sorbae styles may have slightly different fits. Always check the individual product description for style-specific fit notes, and read customer reviews for real feedback on how a particular suit fits on real tween bodies.

What if my daughter is at the very top end of tween sizing (Size 14)?

Size 14 is designed for tweens aged 13 and up. If your daughter's measurements sit comfortably in Size 14, that's the right choice. Sorbae's sizing stops at 14. If she's significantly larger, you might need to explore junior or women's options.

🌊 Know Your Size. Shop With Confidence. Sorbae Sizes 8–14.

A perfect fit starts with accurate measurements and a tween bikini size guide you can actually trust. At Sorbae, every size is designed specifically for tweens, not adapted, not scaled, not guessed at.

When you measure your daughter using the steps in this guide and match her measurements to our size chart, you're buying swimwear that fits her, not wishful thinking about her future size.

Plus, every order comes with a free Bikini Swim Bag, free shipping Australia-wide and internationally, and a 30-day returns window if anything isn't quite right. This summer, get the fit right the first time.

Shop the Collection and find her perfect size in Hibiscus Crush, Limoncello Love, Sea-foam Kiss, or our Bundle. Hand-beaded detail. Sizes 8–14. Designed on the Sunshine Coast for Australian summers.