Sale mountain warehouse is running Load mountainwarehouse.com today and you are looking at three offers before you have clicked anything. EXTRA20UK is the fourth one, and it is the only one with a date I can actually rely on. It gives 20% off and runs to 29 September 2026.
- Free delivery over £50 sits in the top bar.
- A yellow badge promises up to 50% off gilets.
- Clearance has its own permanent slot in the navigation.
That is the thing worth understanding about this shop. The sales rotate. Gilets carry the badge this week, and something else will carry it next week. The code stays put for 20 more days.
Contents
What Is Running At Once
| Offer | What it covers | How long it lasts |
|---|---|---|
| EXTRA20UK | Own brand full price lines | To 29 September 2026 |
| Up to 50% off gilets | One category only | Until the campaign rotates |
| Clearance | End of line stock | Permanent section |
| Free delivery | Orders over £50 | Ongoing, T&Cs apply |
| Student and Blue Light Card | Full price items | Ongoing, applied automatically |
Which One The Basket Takes
One. The code terms say it cannot be used alongside any other promotion or code, and Mountain Warehouse applies membership discounts automatically rather than by code.
So the basket takes a single discount, and you are picking which. A gilet cut by 50% keeps its sale price. EXTRA20UK will not touch it, and you would not want it to, because 20% is the smaller number.
Third party brands and digital gift cards sit outside the code as well. Visit the Brands tab and most of what is in there falls outside.
Why The Code Outlasts The Sales
They run on a banner, they push one product group, and they disappear when the marketing calendar moves on. Gilets today, waterproofs or ski kit next month.
A code with a fixed end date behaves differently. It sits behind everything for 20 days and covers whatever full price stock exists on any given morning. That makes it the tool for the item you actually want, rather than the item the homepage is pushing.
I would rather have that than a deeper discount on a category I was not shopping.
The Comparable Price Asterisk
That is not the same as 50% off what Mountain Warehouse was charging last month. It is a comparison against a reference price, which is standard practice across UK value retail and perfectly legal. It does mean a sale percentage and a code percentage are not measuring the same thing.
The 20% comes off the price on the tag. Nothing about it needs interpreting.
What The Checkout Actually Shows
The code box sits on the basket page at mountain warehouse, type EXTRA20UK in, apply it, and then watch which lines move.
That last part matters more than people expect. The 20% comes off eligible lines only. Anything ineligible keeps its price and still counts towards your total. Put a £60 full price jacket and a £45 reduced gilet in together. The basket reads £105. The code takes £12 off the jacket and leaves the gilet alone. You pay £93.
£93 clears the £50 threshold, so postage costs nothing on a basket that size. Check the discount line before you pay. If it reads lower than you expected, the code has met something it does not cover.
Where The 20% Belongs
New season stock and everyday lines that never reach the sale rail. Walking boots in current colours, base layers, the fleeces that sell all year.
Visit the store, ignore anything showing a struck through price, and apply EXTRA20UK to what is left. A £60 jacket becomes £48. A £35 fleece becomes £28.
Delivery is charged separately below £50, so a small order can hand back part of what the code saved. The gilet badge will have changed by then. 29 September is a Tuesday.
