How to Choose the Right Swimsuit Size Online? 2026 Complete Guide

Buying swimsuits online is convenient, but the biggest fear is receiving an item that doesn't fit – too loose with no support, or too tight and uncomfortable. In fact, as long as you master the correct measurement methods and understand size charts, you can choose the most suitable swimsuit size from home. Here's a step-by-step breakdown of how to select swimsuit sizes online, so you can shop with confidence and wear with pride.

Why is ill-fitting swimwear the biggest fear when shopping online?

Swimwear is intimate apparel, unlike ordinary tees or jackets where a looser fit is acceptable. If the size is wrong, it not only affects your appearance but also means you'll lack support or feel uncomfortable when moving in the water, potentially even impacting your flexibility while swimming or diving. Choosing the right size allows you to confidently show off your figure and fully enjoy yourself.

Before you start: What do you need to prepare?

To accurately measure your body, you will need:

• Soft tape measure: A cloth tape measure is best, ensuring it conforms to your body's curves.
• Mirror: To check if the tape measure is twisted or tilted.
• Correct posture: Stand straight, relax, do not inhale or puff out your chest; measure in a natural state for the most accurate results.

Remember when measuring:

• Bust: Wrap the tape measure horizontally around the fullest part of your bust.
• Underbust: Wrap the tape measure horizontally around your ribcage, just below your bust.
• Hips: Wrap the tape measure horizontally around the fullest part of your hips.

Once you've taken your measurements, record the numbers and then compare them to the size chart.

How to read a Size Chart? Three Key Indicators

NAMI's size chart will list the corresponding bust, underbust, and hip ranges for each size. You simply need to compare your measured numbers with those on the chart and choose the closest size.

For example: if you measure 85cm for your bust, 70cm for your underbust, and 92cm for your hips, these correspond to the M size range on the size chart, so you should choose M. Remember, it's best if all three numbers fall within the same size range for the best fit.

Are there size differences between brands?

Yes! Every brand has different cuts, fabric elasticity, and design styles, so you shouldn't blindly follow the clothing size you usually wear. Even if you normally wear M, you might need to choose S or L for some brands.

The safest approach is: Always check the specific brand's size chart every time you shop online, and compare it with your latest measurements to ensure you pick the right size.

NAMI In-Store Customer Fitting Experience Sharing

Based on real fitting feedback from NAMI in-store customers, we have compiled the following practical advice:

• 155cm / 48kg: Usually, size S fits best.
• 162cm / 53kg, fuller bust: Size M is recommended for better support.
• 168cm / 58kg: Size M is comfortable, while L might be slightly looser.
• If there's a significant difference between your bust and hip measurements: Consider choosing a two-piece bikini so you can select different sizes for the top and bottom.

These experiences can serve as a reference, but ultimately, you should rely on your own measurements.

Should you consider swimsuit style when choosing a size?

Yes! Different styles have slightly different sizing requirements:

• Bikini: Usually has more elasticity, so you can stick to your usual size or go down one size.
• One-piece swimsuit: Requires stronger support, so it's recommended to follow the size chart and not choose a smaller size.
• Thermal wetsuit for diving: Needs to be snug for warmth, but not so tight as to restrict movement. It's recommended to follow the size chart or decide after trying it on.

If you want to see the actual products immediately, you can visit the NAMI Swimwear Collection or the Thermal Wetsuit category page to learn more.

What if you're between two sizes?

If your measurements fall between two sizes, consider the following:

• Seeking support, fuller bust: Choose the larger size.
• Seeking a snug fit, high activity level: Choose the smaller size (but ensure the fabric is elastic).
• First time buying online, unsure: It's recommended to choose the larger size, as a swimsuit that's too tight will be very uncomfortable.

Remember, NAMI's swimwear fabrics have a certain degree of elasticity and will fit better after a few wears, so there's no need to worry too much.

FAQ: Common Questions about Online Swimwear Sizing

1. I usually wear size M; should I also choose M for swimwear?

Not necessarily. Swimwear brands have different cuts and fabric elasticities. It's recommended to re-measure your bust, underbust, and hips every time, then compare them to the specific brand's size chart for the most accurate sizing.

2. Should I wear a bra when measuring my bust?

It's recommended to wear your usual, most comfortable bra, or measure without a bra but maintain a natural standing posture. This will give you the most accurate numbers for when you wear a swimsuit.

3. What if my bust and hip measurements are different sizes?

Consider choosing a two-piece bikini, so you can select different sizes for the top and bottom to ensure the best fit for each part. For a one-piece swimsuit, it's recommended to use your bust measurement as the primary reference.

4. Will swimsuit fabric stretch out over time?

High-quality swimwear fabrics (like the elastic materials NAMI uses) will maintain their elasticity well after multiple wears and washes. However, it's always recommended to follow the washing instructions to prolong their lifespan.

5. Can I return or exchange swimwear bought online?

NAMI offers return and exchange services. However, since swimwear is an intimate item, it's recommended to try it on after receiving it (keeping the tags attached, not cutting them, or getting it wet). If the size isn't right, you can contact customer service for return/exchange details.

6. Why are the numbers on the size chart slightly different from my measurements?

Size charts provide a recommended range, and everyone's measuring technique might vary slightly, so a 1-2cm difference is normal. If you are very concerned, you can contact customer service with your measurements, and they will provide professional advice.

7. Are thermal wetsuit sizes the same as swimsuit sizes?

Not entirely. Thermal wetsuits need to be snug for warmth but not too tight to restrict movement. It's recommended to check the thermal wetsuit size chart and refer to customer fitting experiences before deciding.

Conclusion: Don't be afraid of incorrect sizing when buying swimwear online. As long as you have a soft tape measure, accurately measure your bust, underbust, and hips, then compare with the size chart and reference other customers' experiences, you can easily choose the most suitable swimsuit for yourself. To learn more about swimwear styles and styling inspiration, be sure to browse the NAMI Full Collection and find your ocean style!