Forclaz MT900 -18 down jacket review: Reliable warmth at an unbeatable price

Adrian Wilson

The Forclaz MT900 -18 down jacket is a stripped-back and functional puffer jacket for deep winter escapades when the temperature is well below zero. And all for an unbeatable price.

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The Forclaz MT900 -18 down jacket

A soft, comfortable and impressively warm down jacket, the Forclaz MT900 -18 does an outstanding job of keeping you properly toasty in temperatures well below freezing. With 800-fill-power down, box-wall baffles and a water-repellent shell, it delivers the kind of cold-weather performance you’d expect from jackets triple the price — which makes its £109.99 price tag feel almost too good to be true.

The Good

Excellent warmth to weight

Very packable

Packs into its own pocket

Soft outer

Extra protection on the shoulders and around the cuffs

Incredible value for money

The Bad

Fairly fragile material

Not as good looking as more premium jacket

Forclaz MT900 -18 down jacket review

Forclaz’s MT900 -18 down jacket is a lightweight and super warm puffer jacket from French sports powerhouse Decathlon. The thickest of the Forclaz down range, it promises to keep you warm in temperatures between -5 and -18 degrees Celsius (with appropriate layers), while still being ultra-packable and decidedly portable. And all for £109.99.

Here at the GBAC, we’ve long been big fans of Decathlon. The value for money that you get on all of the lines we’ve tested to date, such as the Forclaz MT900 UL 2-person tunnel tent, has been consistently industry-leading. And while that’s not to say that you should expect the same quality and level of detail in their lines as you might get from more premium brands, they’re kit is just as fit for purpose while sometimes being more than half the price.

Created by Forclaz, Decathlon’s in-house dedicated hiking brand, the MT900 jacket has been designed to be a no-frills warm layer that you can throw over when taking a break on winter adventures. In seriously low temperatures (think -10 degrees Celsius or lower), you could also wear it on the move, but it’d be a rare day in the UK when you’d wear this while hiking. Despite its no-frills design, the jacket is still competitively lightweight, however, coming in at an impressive 570 g (for the large size, the version we tested). This makes it almost 200 grams lighter than the Mountain Equipment Lightline, for example, a down jacket that we rate very highly, and a mere 100 grams heavier than the burly Patagonia Fitz Roy down hoody (a jacket which costs almost four times the MT900).

Coming with glued seams across the front, back and arms of the jacket, the MT900 promises to lock in warmth and keep drafts out by hermetically sealing you inside. It also comes with a cosy hood that fits snug to your head, two large hand warmer packers, pockets inside for stashing gloves and maps while you move, and — something which we hadn’t seen before — lengthy pit zips along both sides of the jacket that allow you to regulate heat when wearing the coat on high output activities. What’s more, the jacket can be cinched tight around your hips and face to lock in even more heat, and the whole thing stashes back down into its pocket. When packed away, the MT900 is about the same size as a 1-litre Nalgene bottle, which is smaller than the ME Lightline and just slightly bigger than the Patagonia Fitz Roy.

Inside the jacket, the insulation is provided by a blend of 85% duck down and 15% feathers, with a fill power of 660. As with all of Decathlon’s down products, the down is traceable and responsibly sourced.

Our experience using the Forclaz MT900 -18 down jacket

To test the Forclaz MT900 -18 down jacket, we took this thing out on numerous escapades up and down the UK through the autumn and winter of 2023. We used it on a rainy walk in temperatures just above freezing in the Chiltern Hills, we took it on a wet and windy backpacking trip across Dartmoor, and we had it on during a serious cold snap during a two-night wildcamping trip in the western edge of Bannau Brycheiniog National Park. For reference, we used the jacket in conjunction with the mid-range Mountain Equipment Lightline and the ultra high-end The North Face Pumori Down Parka, all to understand the performance of three jackets from different price points.

Made out of a 15-denier polyamide fabric, the Forclaz MT900 -18 down jacket is soft to the touch and comfortable to wear. Naturally, however, due to the thin materials used (in order to maximise its packability), the jacket feels quite delicate. You wouldn’t want to wear this charging through any gorse, for example, nor would you would you want to fight your way through a dense forest in it. That being said, along the shoulders and around the wrists, the designers at Forclaz have added additional inserts that protect these harder-working parts against the inevitable wear and tear. Along the shoulders, the thicker lining prevents the straps of a backpack from wearing into the material over time, as well as providing some added weather protection, and the inserts around the wrists prevent any snagging when you plunge your hands in and out of gloves and pockets on cold winter adventures.

Now, while we’re on the subject of weather protection, it’s worth noting that the Forclaz MT900 -18 is not waterproof. Decathlon labels the material ‘water repellant’, but it’s not designed to be fully waterproof. Again, doing so would result in a decidedly less packable jacket, which is one of the main selling points of the MT900. Therefore, you should always ensure you’ve got a waterproof shell handy whenever you’re wearing the MT900 as down loses its ability to keep you warm the second it gets wet.

The Forclaz MT900 -18 used on a brutally chilly wild camp in the western Brecon Beacons.

When it comes to warmth, we found the Forclaz MT900 to be incredibly impressive. Easily market-leading at this price point, the close fit and the ability to cinch everything down meant that we felt just as warm in this jacket as we felt in the Mountain Equipment Lightline and The North Face Pumori. Now, that’s not a scientific statement by any means — it merely ‘felt’ like the MT900 did an equally good job as the other two jackets in the same conditions. But that makes it no less impressive by any means, especially considering the price point the jacket is sold at: When bought brand-new from Decathlon, the MT900 -18 costs £109.99. That’s half the price of the Mountain Equipment Lightline, one-third the price of a Rab Neutrino Pro, or one-fifth the price of The North Face Pumori Down Parka. So, when you consider the warmth, weight and packability you get for that money (which, let’s be honest, are the only three factors that really count for jackets like these), we can’t think of a single alternative jacket out there that rivals the Forclaz MT900 -18.

One final thing worth mentioning is the look of the jacket. And while this isn’t something that shouldn’t really matter, especially when you use this jacket for the things it was designed for, it’s always going to play a role. After all, you’ll probably only be able to use this for the things it was designed for a handful of times a year in the UK. The rest of the time, you’ll end up wearing it around town, walking the dog, or during chilly walks to the pub. And for us, we are simply not huge fans of how the jacket looks. In the next iteration, we’d like to see Decathlon redesign it so users would confidently wear in when not in the hills, but that’s a super minor gripe and doesn’t negate the otherwise excellent job this jacket does at keeping you toasty warm when you have no biological right to be.

Forclaz MT900 -18 down jacket FAQs

How warm is the Forclaz MT900 -18 down jacket?

We found the MT900 -18 down jacket to be very warm; as warm as more expensive jackets from more premium brands.
What activities is the Forclaz MT900 -18 suitable for?

The Forclaz MT900 -18 lends itself well to wild camping and hiking in freezing-cold conditions. You wouldn’t want to wear it during high-output activities, like hillwalking or mountaineering, but it should definitely go on the moment you stop.
How waterproof is the Forclaz MT900 -18?

The Forclaz MT900 -18 isn’t waterproof at all. Decathlon list is as ‘water resistant’, but that’s just to say the DWR coating will stop the water from penetrating the material for a short time in light rain. For use in any sustained rainfall or even a short shower, you will need to wear the MT900 under a waterproof shell.
Is the Forclaz MT900 -18 worth the money?

Yes, we think so. Costing only £109.99 when bought directly from Decathlon, we don’t think there’s a better value down jacket out there right now, especially when you consider the all-important factors of warmth, packability and weight.
How durable is the Forclaz MT900 -18?

The Forclaz MT900 -18 is made of a lightweight 15-denier polyamide fabric, which means it’s not particularly durable. The shoulders and the wrists come with reinforced patches to prevent damage to those areas, but the rest of the jacket could be easily snagged.

Conclusion

Overall, we really rate the Forclaz MT900 -18 jacket. It’s effortlessly functional, toasty warm and, weighing only 570 g, barely noticeable in your pack. It comes with some excellent features, contains responsibly sourced down and comes with Decathlon’s generous 2-year warranty as standard. The thing that continues to impress us most of all, however, is the price: At £109.99, we really don’t think there’s a better value puffer jacket out there right now, especially when you consider the all-important factors of warmth, weight and packability. It performs like a high-end down jacket at a very affordable price point, which – for us – makes it a great choice for sub-zero wildcamps and British winter adventures. Even if it wouldn’t be our first choice to wear to the pub.