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Home / Reviews / Best insulated jackets for warming up post-swim

Best insulated jackets for warming up post-swim

For post-swim or pre-race warming, an insulated jacket can be an inspired purchase. We put four synthetic options to the test

Insulated jackets have become popular over the years for their warmth, practicality and style, and you’re just as likely to see them worn to a pub as you are in the outdoors.

But they’re a great complement to a triathlete’s gear cupboard, too. Especially for early mornings when waiting around before a race or for warming up after a bracing outdoor swim.

The four on review here are being tested primarily on their warmth, for obvious reasons. We’ve considered the amount and quality of the insulation, its ability to loft and how well the jacket keeps warm air trapped inside. We’ve also looked closely at the fit of each jacket, the features on offer and their eco-credentials.

For this test, we’ve decided to focus exclusively on synthetic-insulated options. This is because, in addition to the ethical questions around duck and goose down, we felt synthetic fibre’s ability to stay warm when wet is essential to a triathlete. Every jacket on test is also available in both men’s and women’s versions.

So without further ado, here’s our pick of the best insulated jackets for triathletes.

Best insulated jackets

Montane Ground Control Jacket

Montane Ground Control insulated jacket

Having been designed primarily for climbers who stand still while belaying, you’d expect this jacket to keep you incredibly warm. And it does. It’s filled with two types of PrimaLoft insulation, one of which (ThermoPlume) is designed to mimic down feathers in the way it traps warm air.

It works well, ensuring the Ground Control Jacket is one of the warmest on test. We were also pleased to see that a proportion of that insulation comes from recycled fabrics.

Elsewhere, the Ground Control features excel, with an incredibly cosy, fully adjustable hood, an adjustable waist and three zipped pockets on the outside. There’s also a DWR coating that’ll shed very light rain, but nothing heavier.

Verdict: A high-quality jacket offering warmth when you need it most.

Score: 88%

Finisterre Nebulas Jacket


The Nebulas, according to Finisterre, is its warmest insulated jacket. The ‘A-Form’ insulation uses 100% recycled polyester to mimic the high-loft of down while retaining 75% of its warmth when wet. And it works extremely well, keeping us toasty on even the coldest of days.

It’s also the heaviest and least packable jacket here, but that’s only an issue if you need to bundle it into a small bag while racing or swimming. The fully adjustable hood is equally as cosy, while the soft, lined hand-warmer pockets are great, though these aren’t zipped.

Additional features include an inner zip pocket, elasticated cuffs, an adjustable drawcord hem and an eco-friendly DWR coating that offers a limited amount of water resistance.

Verdict: Unbeatable warmth, great features and perfect for winter.

Score: 90%

Rab Xenair Alpine Jacket

Rab Xenair Alpine Insulated JAcket

As the name suggests, the Xenair Alpine is designed to perform in mountainous conditions. Filled with PrimaLoft Gold Active insulation, 55% of which is recycled, we didn’t find it quite as warm as the Finisterre or Montane options, but it proved more than sufficient down to low, single-digit temperatures.

It has two zipped, hand-warmer pockets and an external zipped chest pocket, comfortable elasticated wrist cuffs, adjustments on the waist and an adjustable hood, all of which boost warmth.

The Pertex Quantum Air outer fabric offers great wind protection and a basic level of water resistance. We’d happily reach for the Rab in spring, summer and autumn, or winter with additional layers

Verdict: High-quality, fully-featured jacket for three-season use, or use with layers.

Score: 86%

Zoot LTD Mauna Kea Jacket


The first thing to note here is that Zoot recommends ordering one size smaller than your usual. We ended up with our normal size (medium) and felt that was right for us, though it was certainly roomy.

The poly fibre insulation proved sufficient down to temperatures of 5°C, but we wouldn’t push it much further without additional layers. Sadly, there’s no adjustment on the waist, hood or cuffs, with rudimentary elasticated hems doing the job.

Two zipped hand-warmer pockets are welcome additions, but the zip pulls are tiny and hard to operate with cold hands. There are two stash pockets on the inner, but they’re rather basic. Meanwhile, the outer offers very basic water resistance, but is good at blocking wind.

Verdict: A warm jacket that’s let down by fit and features.

Score: 78%

Also consider…

Montane Icarus Lite Jacket

Montane Icarus Lite mens jacket

For something with a little less insulation and a much lower price tag, consider the Icarus Lite Jacket. It comes with the same high quality as the rest of Montane’s range and utilises PrimaLoft’s Silver ThermoPlume insulation, which mimics the properties of natural down and is designed to deliver exceptional warmth for little weight.

As such, it will pack down smaller than some of the other options in this list, making it an easier jacket to chuck into a bag when it’s not being used.

Features include two hand pockets, an elasticated hem and cuffs, and an elasticated hood.

Profile image of Rob Slade Rob Slade


Rob Slade is 220 Triathlon's Content Editor. He joined the team in April 2021 and has a background in adventure sports, which he developed during his time as editor of Adventure Travel magazine. Always up for an adventure, he's motivated by good views and regularly uses the scenery as an excuse for taking so long to complete events. While he may lack speed, he always retains his positive disposition, probably because he knows a pint will be waiting for him at the end.