Decathlon Forclaz Waterproof Trekking Bag Cover review: a solid starter sack for bivying newbies

The roomy Decathlon Forclaz Waterproof Trekking Bag Cover is ideal for your first steps into the bivy sleeping experience

Decathlon Forclaz Waterproof Trekking Bag Cover
(Image: © Decathlon)

Advnture Verdict

This is a good sack to start out with when learning the skills for sleeping with minimum kit.


  • +

    Good budget option

  • +

    Generous length

  • +

    Mummy shape


  • -

    Not designed for extreme weather

You can trust Advnture Our expert reviewers spend days testing and comparing gear so you know how it will perform out in the real world. Find out more about how we test and compare products.

Decathlon Forclaz Waterproof Trekking Bag Cover: first impressions

The Decathlon Forclaz Waterproof Trekking Bag Cover is a great way to ease yourself into the art of bivy sack minimalism


• RRP: £39.99 (UK)
• Weight: 420g / 14.5oz
• Length: 225cm / 88.5in
• Width (shoulder & foot): 89cm & 79cm / 33in & 31in
• Materials: 85% polyamide, 15% polyurethane
• Mouth Closure: Full-length access zip and drawstring at mouth
• Features: Integral stuff pouch, “mummy” profile foot
• Colors: Gray and orange 

Suited to summer conditions rather than extreme weather, the Trekking Bag is still an effective barrier against wind and rain, while the almost-full-length zip gives far easier access than wriggling in and out of a mouth-entry sack (which is what you have to do with most of sacks in our Best Bivy Sack buying guide).

The ‘“mummy” design – wider at the shoulder and with a shaped foot box – gives it a more roomy feel than its actual dimensions would suggest, and there’s easily enough space for a sleeping bag to loft properly.

There’s an integral pouch that the sack can be rolled up into, making a neat and fairly compact unit. The colors are a muted grey with orange zip detail which, even if not the natural greens and browns that bushcrafters prefer, still don’t stand out too much.

It is easy to use, with drawstrings for pulling the generous hood into a tight pucker that can be oriented away from incoming wind or rain, and will keep the weather out, while still allowing you to breathe.

Decathlon Forclaz Waterproof Trekking Bag Cover: on the trails

Decathlon Forclaz Waterproof Trekking Bag Cover

The drawstring hood closure works smoothly (Image credit: Decathlon)

Integral stuff sacks in bivies are a real bonus; they’re one less thing to lose in the dark and make bivies that have them, like the Forclaz, quick to deploy. 

The three-quarter length zip makes it easy to get a mat and sleeping bag inside this bivy, and then to get yourself inside. There’s always a price to be paid when you compromise weatherproofing for the convenience of a zip entry, though. In this case there’s a flap over the length of the zip that needs to be fastened down with Velcro tabs and ideally positioned away from the side that rain is coming from. 

The zip entrance is practical, though, as it can be opened up in good weather, a bonus for those who can find “bag”-style bivies claustrophobic. The “mummy” foot gives space around the feet, though those with wider torsos might find this bivy a little restrictive around the shoulders when zipped up in bad weather. 

The drawstring hood closure works smoothly allowing the opening to be puckered down to a small breathing aperture, and there’s enough length for anyone under six foot to have a bit of storage room in the hood, too.

Jasper Winn

After a wild childhood in west Cork, Jasper Winn began embarking on long cycles, walks, horse journeys and kayak trips across five continents – adventures he’s decanted into books, magazine articles, radio and television documentaries. Keen on low-tech but good gear, Jasper is an advocate of slow adventures by paddle, pedal, saddle, boot and sail. He has circumnavigated Ireland by kayak and cycled across the Sahara. Twice. Having ridden north-to-south across Algeria he discovered the only way to get back was to turn round and pedal north again.