Perfect swimsuit 🤍
Seren Onepiece (Longevity) - Medley
£70.00
£3.95 UK shipping or FREE over £90.
We ship worldwide. Rates are calculated at checkout.
ULTIMATE ENDURANCE
Our newest design, built for performance and durability. Featuring double cross-back straps for a secure fit and streamlined feel, this suit is designed for swimmers who train many hours in chlorinated water. Our Seren Onepiece is made using our Longevity-Eco fabric, crafted from recycled ocean plastic.
FAQs
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Please check our sizing page to find your best fit. For personalised help, chat to an expert by emailing support@instantswimwear.com
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Yes! We ship worldwide, and you'll be able to track your order to your door.
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All of our swimsuits are designed for training! Every piece is chlorine-resistant, but our Longevity suits are the most durable.
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We have a super easy returns and exchange process, using our online returns portal. All returns & exchanges must be submitted within 14 days.
Customer Reviews
Overall rating: 4.8 / 5 from 33 reviews.
Amazing swimming costume. I love it. Tall length in this style please, and would love a style with a less high cut leg / more bum coverage. Thanks so much for making such lovely and functional swimwear 😊
I have been looking for a functional, chlorine resistant, but sexy swimming costume forever. I don’t think I will buy one anywhere else now! I love this. If it lasts as long as your reviews suggest I’m a customer for life. My only request would be for a swimsuit version that is not so high cut over the leg / bum to preserve modesty over bikini line! (And tall versions in all types would be lovely!) Thank you- I love it.
Fab swimsuit. Keeps me secure for a swim and super flattering.
I’ve been wearing instant swim bathers for years now and continually get compliments. Best bathers by far!
I love this swimsuit! It’s incredibly flattering, and I always get compliments when I wear it. It also gives me a boost of confidence every time I put it on. The material is nice and thick, which I really appreciate. Overall, it’s the best swimsuit I’ve ever owned!
Brilliant colour and a lovely fit. Material is like a normal training suit material. 4 stars because it does wedgie if you have a booty.
Lovely design and super comfy for swimming !
So comfortable and secure! Love the fit and the colour!
Love the comfort of this suite. It’s practical for swimming, paddle boarding etc while still being cute. Great color too!
My daughter Vita swims 22 miles every month for different charities. She set this goal in January 2025 and is on track to complete 528 miles by the end of the year. Her well-being, confidence strength, fitness, and vitality has gone from 0 to 100% and I'm so proud and happy for her She loves her new instant swim, she looks great and feels fab. Instant swim cossies have a good fit, allowing for shoulder rotation and support in all the right places. They are wearing well , in sea and fresh water and chlorinated pools. Please check and follow Vita on Instagram @vitaswims
Perfect swimsuit! The straps were too tight at the beginning, but loosened a bit. Super comfy! Good quality fabric.
I love this suit for training in! It feels so secure 🩵 going to get it in another colour ✨
I love this suit. However it fits really tight, so if you are unsure with your size and want a more relaxed fit I would recommend to size up.
Love the fit as always and the material.
The shoulder straps are definitely tighter than the Karma One Piece, but it's lovely!
Lovely colour and trim on the swimsuit
Just a girl who loves swimming!!The perfect brand for swim girls with amazing colors of swimsuits!The swimsuit has such a hot color and when i wear it i feel like fire!!The googles are perfect too!keep up the good work we want moreeeee!!
Love this bathing suit, stays in place and very supportive
Loved this! Great fit and great quality, will definitely be buying more
I am obsessed with it! I love the colors, so vibrant, perfect for summer🌞 It’s such a great quality for the price♥️
Slightly short on the body length otherwise a cracking swimsuit, not at all see through, the cut is fantastic and the colours are so unique! Overall I’m so happy that I have ordered two more but I have tryed to purchase one with the long length - I’m 5’8” tall to see if it doesn’t give me such a wedgie 🤣 love the suit !!!!
Great product and a great fit also love the colours
All ok
Love the look and the quality of this swimsuit. I ordered it in red and I can't wait for rhe black one to be back in stock🖤
Very true to size. 5ft 4/ 55kg usually a size Small in speedo. Got a size S (30) was lovely fitting and didn’t gape on the neckline which I found on the Karma! Absolutely love it and have had so many compliments, the material quality is unmatched
Love the colour and style, but it is not true to size. Definitely size up from your regular, I’m usually a 6-8 and wish I bought the 10
Very nice fit and fabric!
I love the colour and the fit!! When I swim it rides up a bit though and gives me a wedgie !
Love this swimsuit! Colour is great for the summer and back /straps design is so flattering!
Love this one piece!! It’s a gorgeous colour and fit
I feel so cute in my new swimsuit. I’m so excited to get in the pool to show it off (and train 😂)! I waited ages before I finally bought it and I’m so glad I finally got it!
It's a beautiful cut, but I'm devastated that it doesn't come in a tall version 😭