icebreaker Women’s Merino Blend 260 ZoneKnit Seamless Jumpsuit – Reviewed & Tested

The icebreaker Women’s Merino Blend 260 Zonekit Seamless Jumpsuit exceeded expectations with its comfort, performance, and durability. Despite minor irritations with the open-back design, it’s a worthwhile investment for high-intensity adventures.

The brand icebreaker (yes, with that annoying lowercase ‘i’) was founded in New Zealand in 1995 by Jeremy Moon to ‘provide natural performance alternatives to synthetic based apparel’. If you haven’t heard of them, try mentioning merino or thermals to a group of outdoorsy people. You’ll no doubt hear the brand icebreaker mentioned with great enthusiasm, loyalty, and respect within a matter of seconds. 

At least, that’s what happened when I was at a navigation course with a bunch of backcountry skiers recently. I wasn’t overly surprised given that icebreaker has built its reputation on providing innovative high-performing gear that lasts. Its latest innovation? The Women’s Merino Blend 260 Zonekit Seamless Jumpsuit, part of the icebreaker 2024 hiking range.

It’s brown but when photographed indoors it appears blue. Is this the next edition of the blue vs gold dress saga?

Why am I the right person to do this review?

This jumpsuit has been designed for running (which is a rare occurance for me) and hiking, which I love, and do often. When I first heard about this little one-piece, I was full of questions. I’ve also never worn icebreaker before so I’ve got none of the cult-esque brand loyalty that anyone who interacts with this brand seems to become infected with. (I wonder if that’ll be me after a few months of jumpsuit life?)

Finally, when you’re considering buying a product, you want to hear the opinion of someone who isn’t afraid to give one, but who’s put it through the absolute ringer. Under my intense scrutiny, this jumpsuit has done everything I’ve done, from riding my bike, to working at a desk all day, walking the dog, short hikes, keeping warm in alpine lodges, gardening, even vacuuming the house accompanied by many decibels. And I’ve got a lot to say.

Throwing this on for my daily walk with the dog was pretty easy, but going to the toilet was annoying so I rarely wore it all day

Quick Specifications

Weight: 180g
Fabric: 38% merino wool, 38% lyocell, 18% nylon, 6% elastane
Colourway: Bittersweet (AKA, brown)
RRP: $249.99

Performance

Durability

Even with only 6% elastane, the Merino Blend 260 Zonekit Seamless Jumpsuit has already proven itself superior to every other merino and synthetic thermal item of clothing I’ve worn. How? By not almost immediately stretching out of shape. The elastane helps the fabric maintain its shape over time, while also adding stretch so it moves with you with no resistance. Granted, the 18% nylon will also be helping in this regard. After a few months of regular wear, I can report that it looks exactly the same as when I first got it. 

Speaking of the nylon – that’s what’s responsible for preventing this jumpsuit from getting too pilly or snagging on things you brush up against. The last thing I want is an item of outdoor gear that I need to worry about in the outdoors. Thankfully, I’ve been traipsing around the state forest out the back of my place every other day and it hasn’t snagged once, despite me forcing it along narrow trails and disturbing many a cobweb. It’s slightly pilly in places (and has been from day one) but this hasn’t increased over time so I’m not concerned with that. 

Fair warning it also picks up every bit of fluff it can, and holds onto it, which is super visible against the brown

ZoneKnit

It’s in the name so it’s gotta be important, right? Yep. ZoneKnit is the icebreaker technology underpinning the construction of the jumpsuit, and all the garments in the ZoneKnit range. The brand has utilised body mapping technology to regulate your body temperature and let your skin breathe optimally during high-intensity activity. This makes it ideal for long bike rides, hikes, runs of all kinds, and even gardening and housework.

Strategically placed merino panels enhance breathability where it’s needed most, and the fabric is reinforced with a thicker knit structure at the back for bottom coverage. It passed the squat test with flying colours and while thin and sleek, has just enough structure to make me feel like I’m wearing more than a bathing suit.

The jumpsuit unfortunately isn’t thick enough to conceal underwear lines – even wearing a seamless pair wasn’t enough to hide them. This is fine if you’re wearing it under trackies or shorts, but it’s bloody comfy to move in on its own, so that was disappointing. I was more than a little self conscious the first few times I wore this out, and I daresay I won’t be the only one. 

The overall fabric composition is naturally odour-resistant. As I’m writing this I’ve just realised that I haven’t washed it yet and it’s been two months. It’s not odourless, but it doesn’t smell enough that I’d consider it unwearable or as having a noticeable smell. Big tick for performance there. 

Read more: I Wore The Same Icebreaker T-Shirt For A Week Straight – Here’s What Happened

The jumpsuit sits firmly and is smooth against your skin. It’s kind of like wearing socks, as you don’t notice it once it’s on

Comfort

Material

The combination of merino wool, lyocell, nylon, and elastane offers that perfect balance of warmth, breathability, and stretch for maximum performance. This is icebreaker’s forte and it’s obvious. From the moment you put it on, you don’t want to take it off. It’s snug without being tight, warm without making you hot, and has the perfect amount of stretch to bounce right back into shape after repeated wears. 

Whoever decided to put 38% lyocell into this jumpsuit is a genius. That’s where the softness is coming from. When I say that this is the softest, smoothest, most luxurious item I own, I’m not exaggerating. It has the same effect as a velvet couch, you can’t help but want to touch it, even while you’re hiking a trail (I’m sure I looked very sane). While it feels phenomenal, the lyocell content in the fabric is the reason why this little number won’t cause you any issues in the chafing department. 

Read more: What’s So Good About Wearing icebreaker’s Natural Fibres in the Outdoors?

Size

A really important consideration when buying this jumpsuit is what size you’ll get. The icebreaker website lists this as a slim fit, and it’s for a reason. This number is designed to be tight and snug so that you can easily layer over the top and so it can perform as intended.

If it’s loose, the fabric is more likely to chafe, let in a breeze or feel lumpy underneath a backpack. If you follow the size guide on the icebreaker website or try it on in-store, you’ll be fine.

I’m in a medium but definitely could go a small in this. If you’re between sizes like me, I’d recommend sizing down

Design

Aesthetics

I like the look of this jumpsuit. The functional requirements have been put first, giving it clean lines that make it look modern and stylish. Eight points to icebreaker for that. I’d have given them the other two points if the fabric was just that bit thicker to conceal underwear lines. 

While I’m not the biggest fan of the colour choice – which for the record I will never refer to as ‘bittersweet’… it’s brown guys, let’s calm down on the quirky colour names – I’ll begrudgingly admit that as far as brown clothing goes, it’s a nice brown. But it’s an odd selection and not one that I think would be as popular as black or navy. Ultimately though, colour is a very small consideration.

It looks pretty good against the trees though – maybe that’s the logic behind it?

Open Back

As much as the open-back design allows for optimum breathability, I’ve got to admit that I’m not a fan. I just don’t understand why we need a hole in the back. Surely the sophisticated icebreaker ZoneKnit technology could handle that section too?

The main way I used this jumpsuit was hiking and walking, mostly with a tee or jacket over the top. Despite the extra breathability of the open back, I then effectively covered the same area with a less breathable clothing item and ended up sweaty there anyway.

My next (minor) frustration with the open back was that while it looks good bra-less in the photos on the website, it looks pretty average with a bra underneath. And I don’t know about the next gal, but if I’m running or hiking, you couldn’t pay me to head out without a bra. The jumpsuit isn’t supportive enough to compensate for the lack of one, and I wish the open back was just a bit smaller (or non-existent) so that I could conceal a bra underneath to maintain the minimalist look of the jumpsuit. Ideally, a bra would have been built in. Maybe in jumpsuit 2.0?

This would look so much nicer either fully enclosed or with a thicker band at the top to conceal the back of bras/crops

Depending on the backpack you’re carrying for a hike, the edges of the seam surrounding the back opening can also rub slightly. I found I could adjust my bag to avoid this and some of my packs were worse than others, but not everyone has the luxury of multiple bags to choose from.

The main advantage of the open back is optimised breathability – after all, no fabric can breathe better than open air. The only time the open back works the way it’s intended is when you’re wearing the jumpsuit by itself with nothing over the top. This is fine, it just means that it’s a little less effective if you have a jumper or tee on during high-intensity activity (at lower intensities, sweat isn’t an issue) and is worth noting.

Functionality

Going to the toilet in this is just annoying. It’s not that bad when the weather is warm, but stripping off a jacket, tee, and then the entire jumpsuit just for a wee… I can’t say I loved getting completely naked every time nature called. I don’t mind so much when I’m home, but when I’m wearing this as my base layer on an overnight hike, stripping everything off for a late-night toilet break is cold.

I did question whether it’d be better to just have a top and shorts, but one: it would be much more expensive, and two: I’d expect a lot more chafing, slipping, and rubbing of fabric. It’s an annoying feature but that’s the trade-off with jumpsuits I suppose.

Sustainability

Whenever a brand admits failure and promises to do better, I instantly respect it more than the one that spends heaps of money tooting its own horn. In 2023 icebreaker committed to being 100% plastic-free. In 2024 the team announced that they didn’t quite get there, and icebreaker is technically only 96.14% plastic-free. The brand continues to work on eliminating that final 4%. It’s not often you see transparency like this and I bloody love it. 

icebreaker has more sustainability commitments than I think you’ll have the patience to read about, but you’ll love their 2028 goal. They want 100% of their wool to be sourced from growers using regenerative practices. It’s part of their commitment to give back more than what they take. 

I have no hesitation in giving these guys full credit for their commitment to helping the planet, transparency, and constant efforts to improve. 

Read more: icebreaker’s Revealing the ‘Uncomfortable Truth of Plastic’ in Our Clothing

14% of icebreaker’s synthetic fabrics have been substituted with bio-based materials in another great step towards regenerative production

Price

I’m always going to baulk at the price of any clothing item over $100. I’m a budget-conscious saver who lurks in the sales section like a seagull – it’s just who I am. But $250 for a highly technical piece of kit that’ll probably last you a lifetime? I think it’s worth it, but it’s a pretty big investment for the average shopper. It’s also cheaper than buying a seperate icebreaker merino T-shirt and shorts or tights. 

Anyone who puts this on is going to want to wear it all the time, even if it’s just as pyjamas when it’s cold (can recommend!). If you add this to your running kit or hiking base layers, you’ll be getting a quality item that you can count on to perform time and time again. Just make sure you’re comfy with the idea of stripping off completely for toilet breaks – $250 is a lot for an item that you don’t end up using on those long runs. 

Thanks to the open back it’s not my first choice for multi-day hiking trips, but for training sessions and day trips without a pack, it was comfy and performed well. 

Honestly, it’s pretty good for daily wear too

Final Thoughts

The Merino Blend 260 Zonekit Seamless Jumpsuit from icebreaker was a product that I wasn’t sure I was going to like – but ever so softly it grew on me, mainly because it was soft. I’m pretty sure I’ve unofficially joined the collective cult following of icebreaker devotees too, despite not loving everything about this jumpsuit. I’ve been lurking on the website checking the lyocell content of other items for weeks in the hopes of adding more silky softness to my wardrobe.

There are a few design elements that could be improved upon should icebreaker bring out another seamless jumpsuit, but in terms of keeping you comfortable while you exercise, it delivers. If you value your function over aesthetics, and don’t mind the open back I’d say you’re likely to enjoy this product.

It took me awhile to understand the merits of this jumpsuit, and while some design features mean that it hasn’t found a home in my multi-day hiking gear, I definitely enjoy wearing it for walking the dog and home workouts

FAQs icebreaker Women’s Merino Blend 260 ZoneKnit Seamless Jumpsuit

Is the icebreaker Merino Blend 260 ZoneKnit Seamless Jumpsuit made from 100% merino wool?

No. The jumpsuit is made from 38% merino wool, 38% lyocell, 18% nylon, and 6% elastane.

What colour is bittersweet?

The icebreaker colour bittersweet is brown.

Is the jumpsuit warm?

Yes, I wore this multiple times to keep warm. It’s really effective at keeping your temperature constant, and is super breathable to avoid you overheating. If you’re not warm before you start moving, just throw a jacket over the top.

Can I wear merino wool in summer?

Yep! Merino wool regulates your temperature and will help you stay cool and comfortable by wicking away sweat.

Will the icebreaker Merino Blend 260 ZoneKnit Seamless Jumpsuit conceal my underwear?

Not well. The jumpsuit is snug and thin and you’ll still see an underwear outline even if you’re wearing a seamless pair. If this bothers you you can always pop some shorts on over the top or experiment with different underwear styles. Let us know in the comments if you find one that works!

What other products are available that use icebreaker’s ZoneKnit technology?

You can check out the full range of ZoneKnit products on the icebreaker website, grab a ZoneKnit bargain from our mates at Wild Earth, or see our initial impressions in our overview of the 2024 range.

Does this jumpsuit show sweat?

I didn’t have a problem with sweat spots appearing in unflattering places. On the contrary, I felt like I was less sweaty than I’d normally be while wearing this. The only time sweat accumulated was riding my bike where I was touching the saddle – makes sense, there was no airflow to wick away the moisture. If you’re running, walking, or moving around you shouldn’t have a problem.