Arcteryx Mens Alpha AR Jacket Thalassa


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Arcteryx Mens Alpha AR Jacket Proteus
Arcteryx Mens Alpha AR Jacket Thalassa

The Alpha AR is a highly versatile mountain jacket that has been optimised to offer you great all round protection and durability whilst not hindering your movement when out climbing and scrambling.


Climbing equipment designed for efficient movement and protection in alpine environments.


Lightweight, minimalist climbing and alpinism products that protect from alpine environments.


High performance weather protection and materials, emphasizing versatility for multiple activities.

Arcteryx Mens Alpha AR Jacket Thalassa

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What is the Alpha AR jacket?

The Alpha AR is a highly versatile mountain jacket that has been optimised to offer you great all round protection and durability whilst not hindering your movement when out climbing and scrambling. It gives you all the tech, features and durability you'd expect from Arcteryx with a climbing and alpinism focus. The 'AR' stands for All Round, which is exactly what this jacket embodies. It will keep you dry and protected from the car, up to the top of the steepest climbs and back down again. 

What is the Alpha AR made of?

The Alpha AR uses two different weights of Gore-Tex Pro fabric to give you a beautiful balance between breathability and durability, which is exactly what you need during high aerobic, non-stop days in the mountains. 3L 40D is used in the main body and 3L 80D reinforcements are used in the high wear areas. This gives the jacket both exceptional abrasion resistance and a surprisingly supple feel.

What are the features?

8mm micro seam taping increases the overall breathability as the only non-breathable part of a membraned jacket is its seam tape. So it only stands to reason that the less area covered by seam tape the more area of breathable fabric there is to transpire moisture. The Jacket also features two external pockets that sit higher, above the harness line (so your phone isn't constantly jabbing into your hip bone) and one internal security pocket (we recommend that any item sensitive to water ingress should be stored in the internal pocket or in an appropriate drybag when the weather gets really gross). The helmet compatible StormHood means you can fit a climbing helmet underneath when needed, but when the extra volume isn’t needed you have adjustments in all the right places to synch it down to normal head size.

Custom Cohaesive hem adjusters double up as HemLock, preventing the jacket from riding up and slipping out under a harness. The Alpha AR also come with WaterTight pit zips that allow you to dump excess heat when you're working really hard.

How does the Alpha AR fit?

The Regular fit cut with e3D Patterning provides a full range of movement with a slightly roomier fit in the body that Arcteryx's 'trim fit' - this will allow for extra layers in the winter without restricting your range of motion. 

Where does the Alpha AR fit in the layering system?

The Alpha AR is primarily designed as an outer shell, more commonly referred to as a hard shell; which means it works well to protect you from strong winds on cold days, right up to torrential downpours.


The Alpha AR is a beautiful jacket for those who are out climbing, scrambling and walking over demanding terrain, and in potentially tough conditions. If you're looking for a do-it-all jacket for your next mountain adventure, then this is it!

  • Lightweight
  • Durable
  • Regular Fit
  • Supple face fabric
  • Breathable
  • Helmet compatible StormHood
  • Strategic 8mm seam taping
  • e3D patterning for freedom of movement
  • 3L 40D Gore-Tex Pro with 3L 80D Gore-tex Pro reinforcements in high wear areas
  • Two external chest-height pockets
  • One internal chest pocket
  • Pitzips
  • Drop hem
Code : 18086-THA-

Season : 2020S A

Weight : 0KG

Sizing Information

Arc'teryx Men's Jackets & Shirts Sizing Information

Measurements refer to body size, not garment dimensions.

  Chest Waist Hip Sleeve
X-Small 36" 29" 36" 32"
Small 38" 31" 38" 33"
Medium 40" 33" 40" 34"
Large 43" 36" 43" 35"
X-Large 46" 39" 46" 36"
XX-Large 50" 43" 50" 37"
  Chest Waist Hip Sleeve
X-Small 92cm 74cm 92cm 81cm
Small 97cm 79cm 97cm 84cm
Medium 102cm 84cm 102cm 86cm
Large 110cm 94cm 110cm 89cm
X-Large 118cm 99cm 118cm 91cm
XX-Large 128cm 110cm 128cm 94cm

Next to Skin Fit: Cut snug to the body through the entire garment to enhance moisture management and thermal efficiency.

Slim Fit: Cut slim to the body through chest, waist, hip and thigh for a low profile fit.

Regular Fit: Cut comfortably from the body through bust/chest, waist, hip and thigh for a classic fit.

Relaxed Fit: Cut loosely through the waist, hip, and thigh for a casual fit.


Measure around your chest/bust, holding the measuring tape under your armpit.


Measure around your waist at the narrowest part.


From a standing position, measure from your crotch to your ankle.


With your arms in a slightly bent position, measure from the centre of the back of your neck, along the length of your arm, to the wrist.


Measure around your hips at the widest part.

Technical Information

Weight: 400g

Fabric: N40p-X 3L Gore-Tex Pro with N80p-X 3L Gore-Tex Pro reinforcements

Centre back: 78.5cm/30.9in, Drop hem

Care & Advice

Care and maintenance

To keep your outdoor clothing and equipment in tip top condition and performing to its maximum we recommend the use of Nikwax products. We have been using Nikwax products since day one (26th March 1986) and have found them to be totally reliable, dependable and effective. Today’s Nikwax treatments contain environmentally friendly elastic water-repellent polymers that bond to fabric fibres, leaving the spaces between open and breathable. These stretchy polymers are able to stretch and move with the fabric so they stay put for longer and work better.

Nikwax treatments will not change the look or feel of the fabric and they are all water based, environmentally safe, non-flammable and contain no nasty Fluorocarbons. Nikwax products can be used to clean, re-proof and revitalise all your outdoor technical clothing and equipment.

Waterproof breathable clothing has a durable water-repellent (DWR) finish applied to the face fabric during the manufacturing process. The DWR forces water to bead up and roll off the surface therefore preventing the fabric from absorbing moisture. If the outside of your jacket is soaked in a layer of cold water, the warm damp air within can’t escape and will condense on the inside. This makes the jacket feel cold clammy and can make you think that it’s leaking. The DWR finish is not permanent and needs to be maintained and revitalised to optimise performance.

This three layer waterproof jacket should be cleaned regularly with Nikwax Tech Wash; I wash my jacket about once a month, or more often if it gets really filthy. Regular washing with Tech Wash will maintain the DWR for longer and remove salts and oils that can contaminate the fabric, and it will keep your lovely jacket clean and smelling fresh. Washing can be done in a machine according to the manufacturers care guidelines (on the internal label). First clean out any detergent and conditioner residue from the machine dispenser and then add the required amount of Tech Wash and away you go. Hand washing is also suitable but be sure to rinse the garment well.

When you notice that rain/water is no longer beading up and rolling off it’s time to re-proof. Nikwax TX Direct will re-instate a long lasting DWR to completely rejuvenate your jacket. Re-proofing can also be done in the machine once a garment has been washed. Just add the TX-Direct and use the same programme you used for washing. You can also use the spray-on product on a damp garment that has just been washed.

You wouldn’t buy a Ferrari and never have it serviced, so make sure you regularly wash and re-proof your quality kit.

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