Editor rating:
8/10 on
User's rating:


  • Lightweight
  • Confident traction from Continental outsole
  • Perfectly snug fit
  • Nimble


  • Runs a full size big
  • Medium-high arch
  • Stark white upper shows dirt easily


The Adidas Adizero Boston 9 is a classic distance flat in all the best ways. It is lightweight, snug, and very durable for a racing flat.

Simple but speedy, the Boston 9 is constructed on the same platform and retains many of the same features of the Boston 8. This shoe is perfect for road racing and fast workouts on pavement or the track.

The Boston 9 is intended to handle marathon mileage and racing, however the shoes do not have adequate cushioning under the forefoot for marathoners over 3 hours or heavier runners.
AdiZero Boston 9
9 oz. (255 gr.)
120 US$
10 mm
Heel Drop
Previous model
Neutral runners with relatively narrow feet and medium-to-high arches interested in a durable distance trainer for road or track workouts.

Adidas AdiZero Boston 9 Intro

The Adizero Boston 9 is designed for marathon workouts and racing. Weighing in at 7.8oz for the women’s model and 8.4 oz for men, this shoe will not weigh you down on long runs.

I tested the Boston 9 on the road and paved paths with some gravel sections. The shoes perform best on pavement, but are sturdy enough to handle short stretches of gravel or dirt.

They are exceptionally responsive for workouts and faster paces. The Boston 9s are nimble and quick off the ground with superb control when rounding a corner, changing directions, or crossing wet surfaces.

They are well-cushioned for a racing flat, however I don’t feel it is enough for a full marathon unless you’re racing under 3 hours.

Adidas AdiZero Boston 9 First Impressions

Adidas AdiZero Boston 9 - Pair

Adidas AdiZero Boston 9 – Pair

A timeless distance racing flat with modern construction, the Adizero Boston 9 is simple, yet powerful as a racing shoe. From the minute I laced up the snug upper, I felt compelled to run fast in these shoes.

On the first run, I felt speedy and confident with every step thanks to the superior traction of the Continental rubber outsoles. The ride was snappy and smooth.

The only feature that detracted from the euphoric lightweight feeling was the somewhat prominent arch.

I was also concerned about stepping in any mud or dirt on the first run since the Boston 9s are a very bright and vulnerable white.

Adidas AdiZero Boston 9 Sole Unit

Adidas AdiZero Boston 9 - Sole

Adidas AdiZero Boston 9 – Sole

The Adizero Boston 9 pairs Adidas’ signature Boost foam (TPU pellets) in the midsole with a Lightstrike EVA foam topsole for a responsive and lightweight ride.

While these shoes are softer and more cushioned than racing flats for shorter races, it’s still not quite enough for a marathon, in my opinion.

I have raced the Boston Marathon, in addition to a few others, and know for a fact that the ball of my foot requires more cushioning when it comes to that last 8 miles.

My marathons fall between 3:07-3:17, so for faster runners coming in under the three-hour mark, these shoes could be just fine.

The cushioning is certainly not substantial enough for heavier marathoners. It is designed for faster racing and competitive runners.

Adidas AdiZero Boston 9 - Sole

Adidas AdiZero Boston 9 – Sole

The midsole also utilizes a thermoplastic platform in the midfoot for some added stability. Adidas calls this feature the Torsion system and has been using it in their shoes for years.

I have always questioned whether this system really provides any technical advantage or if just adds to the shoe’s weight.

That question is still unanswered by the Boston 9. My instinct is that the shoes would be just fine with out it.

The Boston 9 arch is relatively high compared to the Saucony models I typically train and race in. It definitely took some getting used to. These shoes might not be the best option for runners with low or flat arches.

The Boston 9s continue to employ a Continental blown-rubber outsole in a grid pattern that delivers the best traction I have ever experienced in a shoe.

A tight grip is critical for a racing flat intended for high speeds. In the Boston 9s I could confidently round a tight corner without losing much momentum.

The confidence inspired by such supreme ground control can be a powerful weapon on race day, knowing that you don’t have to slow down for a turn, especially in wet conditions.

Adidas AdiZero Boston 9 Upper Unit

Adidas AdiZero Boston 9 - Closeup

Adidas AdiZero Boston 9 – Closeup

The Boston 9 upper is constructed of a dual-layer lightweight and highly breathable mesh. The Coolever interior mesh liner is designed for optimal heat exchange to keep your feet cool.

A flat should hug the foot tighter than a trainer, and the Boston 9 is slim and form-fitting, but not constrictive. The toebox is on the narrow side, but still provides space for adequate toe-splay.

The laces provide a tight fit and should be loosened if wearing thick socks. The tongue is thin and discrete and stylistically resemble the retro look of the Adidas Originals line.

The 2020 unisex colorway is bright-white with subtle details honoring the Boston Marathon such as the B.A.A logo printed on the heel and tongue. The result is a very sleek and professional looking shoe.

Adidas AdiZero Boston 9 Conclusion

Adidas AdiZero Boston 9 - Top

Adidas AdiZero Boston 9 – Top

The Adidas Adizero Boston 9 is an ideal racing shoe for distances 10k and up. The lightweight, responsive flat compels you to run fast and encourages quick turnover.

While I personally don’t think the shoe offers enough cushioning for a full marathon over three hours, the Boston 9s will be my go-to flat for half marathon and 10k speed workouts and races this summer and fall.

We purchased a pair of Adidas AdiZero Boston 9 from runningwarehouse using our own money. This did not influence the outcome of this review, written after running more than 50 miles in them.

Adidas AdiZero Boston 9 Price Comparison

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