Keen Tempo Flex hiking trainer boot review: an innovative fabric hiker

Keen's new Tempo Flex boot boasts a clever rubber section designed to make it feel more flexible around your foot. Does it work? Here's our review

Keen Tempo Flex hiking boot review
(Image credit: Sian Lewis)
T3 Verdict

The Keen Tempo Flex stands out among trainer-style hiking boots – it manages to be solid, supportive and lightweight. Keen's new Bellows.Flex technology adds comfort over long distances, and there's enough breathability and waterproofing to make the Tempo Flex work for more casual hiking adventures from spring through to autumn.

Reasons to buy
  • +


  • +

    Very flexible

  • +

    Solid support

Reasons to avoid
  • -

    Not as breathable as some summer boots

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    Pastel colourways may not suit all tastes

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The latest lightweight hiking boots do away with traditional leather and heavy soles – meet the trainer/hiker hybrid, designed to combine the light weight and comfort of your favourite sneakers with the support and waterproofing you'd find in the best hiking boots. Keen's trainer-hiker Tempo Flex boot only launched in February 2021, but it's already caused a bit of a splash in the outdoor world thanks to its innovative Bellows Flex technology, which is designed to help the boot to flex as your foot does. So how well does it work? Are these boots good enough to be included in our best women's hiking boot ranking? Read on for our full Keen Tempo Flex hiking boot review. 

Keen Tempo Flex boot review: design and features

Keen's latest addition to their casual hiker range packs in some new design – the Tempo Flex boot features the brand's innovative Bellows.Flex technology, a bendy rubber section over the top of the foot that aims to flex with your toes as you walk, making each stride easier while also avoiding wear and tear. 

At 370g, the Tempo Flex is definitely in the lightweight category, but it still packs a technical punch - a Keen.Dry waterproof membrane is water resistant enough to take you through stormy weather, and the boots are surprisingly solid and supportive around the foot and the ankle, with a good tight-fitting lacing system. 

Keen's boots often come in cheerful colourways that make them stand out from boring grey and brown boots, and the sneaker-style Tempo Flex is no exception. The female version of the boot is available in various pastel colourways, although the blue/pink combo we tested and the bright violet version may not suit everyone's taste. 

Keen Tempo Flex hiking boot review

(Image credit: Keen)

Keen Tempo Flex review: performance and comfort

Like most Keen boots we've test out in the past, the Tempo Flex is comfortable straight out of the box – we unpacked our new pair and immediately set off on an eight-mile coast path walk, which could be foolhardy in other boots but was absolutely fine in this model. The Tempo Flex isn't quite as breathable as some lightweight summer hiking boots we've tested out, but it does still keep feet cool enough to tackle summer temperatures, and the mesh, padding and ripstop material in its makeup mean it's also warm enough to work well as a three-season boot – if you already own a heavy winter boot, this is a nice second pair for more relaxed rambles over the rest of the year.

Despite their light weight the Tempo Flexes feel solid and supportive underfoot, with a good lacing system that allows you to lace them snugly around the ankle. The boots feel supportive even on rough terrain, unlike many other flimsier trainer-style hiking boots. The soles do feel quite flat - hikers in need of arch support may need to look elsewhere. The Tempo Flexes feel like they're aimed at more relaxed hikers who are sticking to trodden paths, and this is reflected in the sole, which offers good grip on trails and rock but isn't sticky enough to tackle mud and wet mountainsides. 

Keen Tempo Flex hiking boot review

(Image credit: Sian Lewis)

Keen Tempo Flex hiking boot review: verdict

Put simply, the Tempo Flex is a great three season boot for hikers who don't stray too far from the beaten trail. We're not sure the Bellows.Flex technology revolutionises the hiking boot market, but it definitely does make the boots feel more flexible underfoot than others with a similar design and price point – coupled with a light weight and great solid support, the Tempo Flex is a quality choice that won't weigh you down over long distances in warm weather.

Sian Lewis

Sian Lewis is an award-winning travel and outdoors writer, author and influencer. She's the author of popular blog and book The Girl Outdoors, and when

she isn't writing or travelling she spends most of her time hiking, cycling and wild swimming across Britain, testing out the latest adventure gear and clothing as she goes.