Product Colors and Sizes

  • Black Friday product
  • New Deal product
  • Cyber Monday product
  • Clearance product
  • Deal product
  • Best Seller product
  • Ecodesign product
  • New product
  • Staff Pick product
  • In The News product
  • Innovation product
  • product


Sale price: $44.99 Regular price:

Perfect for drinking while running, give it a try!

Color: Select a color
Size: Select a size
Sale price: $44.99 Regular price:

Free shipping over $35

Free returns

Free pickup

San Francisco, 735 Market St. Options

Select an available color and size to see options.

Model: 8312245

Product Videos

Product Features

A photo of the MEN'S RUNNING TRAIL BAG in use


Perfect for drinking while running, give it a try!


14L in front and back pockets, gusset for reduction to 9L

Multiple compartments

Separate compartment for 2L water bladder (sold with bag).

Easy to use

2 large (0.5L) chest pockets for easy access to supplies.

Product Customer Reviews

Skip to reviews
1250 Reviews
Write a Review 

Filtered by reviews Loading reviews…
Trail Running Vest/Bag

Picked this trail running best to support my first 50 mile mountain run. In the sales for just £12.99! Well made piece of kit that seems really comfortable after first few 5-10 mile runs. Only criticism would be that there could do with being s couple of elastic loops round main straps to prevent flapping about. Can get round it by using a couple of hair ties. Would recommend to all at such an amazing price

icon-circle-checkmark verified purchase
good piece of kit

lightweight with good size compartments in the back, and drinks bottle holders are ideal for a standard 500ml bottle, the clasps are a bit awkward to do up, whistle is handy (hoping not to use it though) side pocket is right size for a phone, although a little awkward to reach when on the go, option to remove the bladder to create more storage

icon-circle-checkmark verified purchase
Excellent product low price better than expected

I would recommend it to anyone for long runs as it keeps you hydrated and has virtually no weight.

icon-circle-checkmark verified purchase
Would recommend

Great bit of kit considering the price. Comfortable with lots of adjustment available to get it right. Maybe pockets are a little tricky to get to whilst running, but still does the job.

Nice weight, size, look, but just 1 problem

Bag bought on sight as it Looked just right for the event I was to use it in (Braveheart Triathlon) Tried it on it the store and it fitted just right, even stuffed a couple of water bottles in the front holders to check they'd sit low enough whilst wearing it. So bag bought along with a couple of other essentials, hat gloves... On taking the bag home it was time to fill it with all the mandatory and essential kit for a day on Ben Nevis, and hey presto everything fitted in (nice capacity) even with a 1.5L of water in the bladder. Now this is where the real problem begins (well in my eyes anyway) Once you have filled the pack and got it sitting just right on your back, that 2 side pockets, that you'd put your snacks to eat on the go in, well they are just unreachable, and if you do manage to open them, then I'd suspect that all the contents would end up on the trail your running along.. To use these pockets properly you'd have to stop and take the pack off to get the stuff out, somewhat defeating the point of eating on the go really.. The bag itself is well made lightweight and holds more than it looks, so top marks for that, but you need to look at the placement of the side pockets. Bag returned and upgraded to the 12l walking pack.. I'd recommend the pack as it will do what it says, but just be mindful of the side pockets, you need to be an octopus or double jointed to use them.

icon-circle-checkmark verified purchase
Worth every penny

Great value for money and as good as the expensive ones, very comfortable to wear , I would 100% recommend this to anyone

icon-circle-checkmark verified purchase
Solid Pack

Bought this product as I'm doing an endurance race and needed something to carry the mandatory kit. This is a good pack that meets the requirements for the race. Just enough space inside when expanded to fit what I need regarding waterproofs, warm clothing and race snacks. The bladder is a good size but can't be filled completely as there is a little leakage from the top. The front pockets, whilst designed for bottles, are great for keeping gels and other bits in for easy access. Good price and does the job nicely

icon-circle-checkmark verified purchase
Great Value

Just started training for an Ultra, well, still at 10km really! Didn't want to spend over £100 this early in my running training. This product is great, very little bounce even when crrying 2ltr of water in the back, plenty of space for a waterproof jacket and gels. I used salomon 250ml soft flasks in the chest pockets and these fit really well, larger bottles will also fit but don't feel as secure to me. The one negative I found is the quality of the drinking bladder is quite poor (But they have to save money somewhere) I just replaced with one I already owned. The chest straps appear flimsy but are not showing any signs of wear and tear yet. Just as an extra note, I also purchased the running chest light that Decathlon do, I wore this along with this pack, and didn't experience any extra rubbing during a 10km night run. Highly recommend this product.

Perfect for long distance running training

I hardly notice I'm running with it. Front pockets are easily accessible and hold all I need. Side pockets are a little awkward to access when running. There is a waterproof pocket in the back for your mobile phone. I've tested this in heavy rain and my phone was bone dry. LIkewise, there is a separate (from the bladder) section in the back for dry clothes. Again, my t-shirt was bone dry. There's room for more but that's all I had in it. The bladder is good as well. Remember to remove all the air after filling to eliminate water sloshing noise. The front straps are pulled very short when it arrives. I found it comfortable with the shoulder straps far apart.

icon-circle-checkmark verified purchase
Kalenji Running Trail Bag

Excellent trail bag. I bought it because it received 'Best Value' in 'Packs Put to the Test' in Trail Running magazine. It is comfortable to wear and I did not have any hot spots from rubbing over 1/2 marathon distance.. The bag fits well and their is no excessive movement. The straps are easily tightened during a run as the volume of fluid in the bladder decreases. There is plenty of storage space for clothing, food and other accessories. In my opinion this is much better than any similarly priced bag and is comparable to the more expensive trail bags on the market. The only thing that I would change are the buckles on the bag which seem a bit flimsy, but they haven't given any problems so far.

icon-circle-checkmark verified purchase
Trail Hydration vest

Awesome bit of kit plenty of storage, see through side mesh pockets allow you to see whats in them. Chest straps keep everything tight and front pockets or bladder gives multiple options for fluid. And at a fraction of the cost of other market brands

icon-circle-checkmark verified purchase
Confortable and well worth the price

Great bit of kit for the price. Comfortable and cleverly designed to maximise space. Could have a few more pockets on the front straps but over all very happy.

icon-circle-checkmark verified purchase
Best £25 I ever spent

This is a cracking little pack, worth every penny/ Fits nice and snug and has plenty of space. In summary, save the £100 you would pay for a big name version and buy this instead!

Men's running trail bag

Excellent bit of kit for the price. Took a bit of time to get the fit just right. But now it's set up I find it comfortable,the two front pouches which should house bottles I use for my phone and a snack. The bladder has an excellent huge filler neck,easy to fill and empty. Only two criticisms the water in the bladder gets warm quickly, even when you fill it with some ice,and it sloshes when you run,but once tour used to the noise,it's not a worry,unless your trying to creep up on people.

icon-circle-checkmark verified purchase
Kalenji trail bag

Comfy and plenty pockets love it

icon-circle-checkmark verified purchase
Skip to reviews

Additional Product Information


Outer fabric: 100.0% Polyamide ; Inner fabric: 100.0% Polyester cationic


weight: 16.2 oz with water bladder

Water bladder:

Capacity:2 litersLength: 15” Width: 7”hose length: 100 cm.

Safety whistle

110 decibelsstored in a small chest pocketcompulsory for many races (TRAIL RUNNING)

Chest pockets

There is room for 500ml water bottles (sold separately).

Storage instructions

do not leave water in the bladder more than 24 hours. Rince well using clean water after use and allow to dry before storing away.



Superior quality. Unbeatable prices.

For 40 years, Decathlon has delivered the best value in the retail sports industry by offering high-quality, sustainable and cost-effective products.

Decathlon makes the difference
  1. product-research

    Research and development

    delivers high-quality cost-effective products

  2. State-of-the-art production processes

    minimize manufacturing costs

  3. Optimized supply chain

    reduces retail prices

  4. laptop-checkout

    Minimal retail footprint

    lowers overhead and indirect costs


Size Guide Visual