Bikini bottoms
"Very nice bikini bottoms however I bought them in the sale and they didn’t have the 8-10 available. I thought the 10-12 would be ok but they were too large. No returns on the sale items but my daughter is delighted with them."
| S | M | L | XL | 2XL | 3XL | |
| Size Conversion | ||||||
| AU | 8-10 | 10-12 | 12-14 | 16-18 | 20-22 | 24-26 |
| US | 4-6 | 6-8 | 8-10 | 12-14 | 16-18 | 20-22 |
| Bust | ||||||
| CM | 87-93 | 93-99 | 99-105 | 106-114 | 115-123 | 124-130 |
| IN | 34-37 | 37-39 | 39-41 | 42-45 | 45-48 | 49-51 |
| Waist | ||||||
| CM | 67-73 | 73-79 | 79-85 | 86-94 | 95-103 | 104-112 |
| IN | 26-29 | 29-31 | 31-33 | 33-37 | 37-40 | 40-44 |
| Hips | ||||||
| CM | 97-103 | 103-109 | 109-115 | 116-124 | 125-133 | 134-142 |
| IN | 38-40 | 41-43 | 43-45 | 45-48 | 49-52 | 53-56 |
For leggings, the hip measurement is the most important for finding your perfect fit, especially if you're between sizes.
Hip: the widest part of your hips making sure the tape measure is even over your bum
Waist: your natural waistline above your belly button and below your rib cage
Bust: the fullest part of your bust at nipple level
Send your measurements to hello@activetruth.com for personalised advice from our fit experts.
| S | M | L | XL | 2XL | 3XL | |
| Size Conversion | ||||||
| AU | 8-10 | 10-12 | 12-14 | 16-18 | 20-22 | 24-26 |
| US | 4-6 | 6-8 | 8-10 | 12-14 | 16-18 | 20-22 |
| Bust | ||||||
| CM | 87-93 | 93-99 | 99-105 | 106-114 | 115-123 | 124-130 |
| IN | 34-37 | 37-39 | 39-41 | 42-45 | 45-48 | 49-51 |
| Waist | ||||||
| CM | 67-73 | 73-79 | 79-85 | 86-94 | 95-103 | 104-112 |
| IN | 26-29 | 29-31 | 31-33 | 33-37 | 37-40 | 40-44 |
| Hips | ||||||
| CM | 97-103 | 103-109 | 109-115 | 116-124 | 125-133 | 134-142 |
| IN | 38-40 | 41-43 | 43-45 | 45-48 | 49-52 | 53-56 |
For swimwear, measure your hips, waist and bust.
Our swimwear is made to fit up to an G cup. If you are between sizes we generally recommend you size down, unless you are above an E cup.
Hip: the widest part of your hips making sure the tape measure is even over your bum
Waist: your natural waistline above your belly button and below your rib cage
Bust: the fullest part of your bust at nipple level
Send your measurements to hello@activetruth.com for personalised advice from our fit experts.
| S | M | L | XL | 2XL | 3XL | |
| Size Conversion | ||||||
| AU | 8-10 | 10-12 | 12-14 | 16-18 | 20-22 | 24-26 |
| US | 4-6 | 6-8 | 8-10 | 12-14 | 16-18 | 20-22 |
| Bust | ||||||
| CM | 87-93 | 93-99 | 99-105 | 106-114 | 115-123 | 124-130 |
| IN | 34-37 | 37-39 | 39-41 | 42-45 | 45-48 | 49-51 |
| Waist | ||||||
| CM | 67-73 | 73-79 | 79-85 | 86-94 | 95-103 | 104-112 |
| IN | 26-29 | 29-31 | 31-33 | 33-37 | 37-40 | 40-44 |
| Hips | ||||||
| CM | 97-103 | 103-109 | 109-115 | 116-124 | 125-133 | 134-142 |
| IN | 38-40 | 41-43 | 43-45 | 45-48 | 49-52 | 53-56 |
For maternity leggings, the hip measurement is the most important for finding your perfect fit.
We've designed our pregnancy leggings with plenty of room for your growing bump, so don't use your waist measurement.
Hip: the widest part of your hips making sure the tape measure is even over your bum
Waist: your natural waistline above your belly button and below your rib cage
Bust: the fullest part of your bust at nipple level
Crops
Due to the changes your body experiences during breastfeeding, we recommend comparing your under bust measurement (where your bra band sits) to the sizing chart below.
Our nursing crops cater up to a DD cup. For larger cup sizes you may wish to size up.
| S | M | L | XL | 2XL | 3XL | |
| Underbust | ||||||
| CM | 74-80 | 80-86 | 86-92 | 93-99 | 99-106 | 106-112 |
| IN | 29-31 | 31-33 | 33-36 | 37-39 | 39-42 | 42-44 |
What makes the Byron Bikini Bottom work

A high rise and a mesh panel smooth your tummy and hold everything in.

Enough bum coverage to feel secure, and no riding up when you swim.

Soft, thick and no see-through surprises when it's wet.

Pair with the Byron Bikini Top or Coolum Tankini, sized separately so each half fits.
What women ask us most about the Byron Bikini Bottom.
Byron High Waisted Bikini Bottom comes in sizes 8 to 26. If you're between sizes, go down. It's sold separately from the tops, so choose the size that fits your bottom half.
It's a high rise that sits over your tummy, so it won't roll down, even when a wave dumps you.
Yes. A mesh panel through the front smooths your tummy without squeezing.
Enough to feel secure. Not too skimpy, not too frumpy, and it stays put when you swim.
No. It's double lined.
The Byron Bikini Top or the Coolum Tankini, sold separately.
Yes. All Active Truth swimwear is made from chlorine-resistant fabric, so it's built for pool laps, aqua aerobics and regular swims.
Yes. All our swimwear is rated UV 50+.
We offer exchanges to help you find your perfect fit and accept returns for 30 days from the date of purchase. Returns for refunds are only available for items purchased at full price.
Items marked Final Sale can't be refunded, returned or exchanged. See our returns policy.
Yes. Shipping is free on orders over $200.
★★★★★ 4.8 from 305 reviews
First Bikini in 30 years!
"I have a bit of a double tummy so I loved that the bottoms were actually high wasted enough to cover my belly bulge above my belly button! Thank you!"
So comfy!
"The most comfortable swim bottoms ever!!! They stay in place, don't ride up anywhere and have the softest waistband which sits perfectly. I now have 3 pairs!"
Best swim bottoms ever
"Super comfy bottoms with good bum coverage and a waist that fits in all the right spots"
Overall rating: 4.8262296 / 5 from 305 reviews.
The Byron High Waisted Bikini Bottoms offer a great fit, high-quality material, and excellent coverage. The fabric is luxurious and comfortable, enhancing the overall look and feel. The quality is highly praised, making it a must-have for beach adventures.
Review topics: [size, fit, feel, colour, shape, look, fabric, pants, material, quality, comfort, pair, style, stretch, coverage, leggings, cut, waist, texture, bottom, height, bikini, swimmers, swimwear, piece, set, waistband, bathers, support, tankini].
"Very nice bikini bottoms however I bought them in the sale and they didn’t have the 8-10 available. I thought the 10-12 would be ok but they were too large. No returns on the sale items but my daughter is delighted with them."
"First bikini I’ve worn in years (especially since my C-section!) and I love it! Amazing quality, fabric and fit. I’m a 12DD–E and usually 10–12 in bottoms. Medium in both pieces fits beautifully. Thank you, Active Truth!"
"As a larger chested person (12G) I found this set were able to contain and support - I already had a one piece in this fabric in a large and as I prefer a firmer fit this time around I ordered a medium and it worked well. The only minor thing I don't like about this set is the hooks and eyes are silver, and I would prefer they were black to be less 'bra' looking. Still comfortable and functional and a great buy when on sale."
"Loved my navy Tankini and bottoms, both super flattering and showed all the right places but hid all the ones I wanted to. Very comfortable and soft material, only down side was the tankini didn’t come with any padding. Other than that, great set 👍"
"The quality of the fabric and cut of both top and bottom are very comfortable and flattering. I did put some padding in the top as I have no natural shape left and it helps! But most of all, I want to rave about how wonderful the customer service is. I had to return an item and it was a quick and easy process, but I then ordered the wrong colour in my exchange. I was so upset, but they responded quickly to my cry for help and let me send back the sale item for the correct one. Very reassuring and responsive all the way!! Thanks heaps. Have recommended your products to friends!"
"I am enjoying my comfortable, no crease, easy wash, quick dry gear from Active Truth. Just back from Europe where I felt comfortable & well dressed in comfy tops & pants. My swimmers have arrived & the girls at Aquarobics are envious. These garments are timeless & coordinate well with my existing wardrobe."
"These high waisted bikini bottoms aren’t as firm as the top, still very comfortable but would have loved a little firmer fit. Maybe I need to go down a size next time. Still happy with the tankini set."
"These are maybe a size too big but still feel good. They do come up high but I am also short waisted. I love a two piece ( but not bikini) for travel especially."
"I had purchased bathers and loved them. Trying to get my daughter interested. So… guess what she got for a birthday gift. She loves them. Can see her confidence when she wears them. Two piece but looks like a one piece. Great versatility."
"Great colour and fit. Holds in place really well even in waves."