Our verdict

In our opinion, the Boston 12 marks a welcomed return to the shoe's roots, evolving as a light, versatile, and universally appealing running partner. It's once again designed to handle a range of runs, from moderate recovery sessions to tempo intervals. The updated Lightstrike 2.0 foam boosts bounce and softness, complementing the brilliant Lightstrike Pro. In our tests, we believe that this iteration makes a significant leap from its predecessor, showcasing smoother transitions, a more comfortable ride, and a lighter build.

Pros

  • Lightstrike 2.0 brings a remarkable upgrade
  • Delivers a fun ride
  • Lighter than versions 10 and 11
  • Handles both slow and fast paces with ease
  • Wide toebox
  • Durable and grippy Continental outsole
  • Even more Lightstrike Pro superfoam
  • Improved stability due to a broader base
  • Fantastic for midfoot-to-forefoot strikers

Cons

  • Upper durability falls short
  • Tongue and heel could benefit from extra padding
  • Heel strikers might prefer v11

Audience verdict

91
Superb!

Who should buy

The upgraded Adidas Adizero Boston 12 is a truly impressive shoe, and here's who we think will love it the most:

  • Midfoot-to-forefoot strikers looking for a training partner with outstanding grip.
  • Those who are fans of the Boston series but felt let down by the heavier weight of versions 10 and 11.
  • Any runner in need of a versatile shoe that can handle all sorts of training runs, regardless of how fast or long they might be.

Adidas Adizero Boston 12

Who should NOT buy

If you're in the market for a soft, flexible running experience, we believe the Boston 12 might not be your shoe. While it's softer than its predecessor, it still delivers a somewhat firm and stiff feel underfoot. In that case, the ASICS Novablast 3 or the Hoka Mach 5 could be better all-rounders.

We also think there are better options if you plan to use the shoe for pure racing or track workouts. It's a bit too heavy for those purposes, and if budget isn't a concern, the Adizero Adios Pro 2 is likely a superior pick. On the other hand, if you're looking for a budget-friendly shoe for fast runs or short races, consider the Adizero Adios 7.

Adidas Adizero Boston 12

Breathability

Absolutely AMAZING. That's the best way to describe the breathability of the Adidas Adizero Boston 12, based on our smoke-machine test results in the lab. It earned a perfect score—5 out of 5.

The light test also confirmed this outstanding breathability. The upper's thinness was easily observed as the light passed right through.

After reviewing the upper, we noticed eight well-placed ventilation holes on the sides—an important addition to boost airflow in this often-overlooked area.

To delve deeper, we took out our trusty microscope to explore the shoe's impressive ventilation.

Adidas Adizero Boston 12 microscope

What we found was a remarkably thin and breathable mesh from Adidas. Clearly, there's no need to have huge ventilation holes in the upper with this clever design in place.

Adidas Adizero Boston 12 microscope

Under the microscope, the upper of the Boston 12 presents an impressive and mesmerizing sight.

Test results
Adizero Boston 12 5
Average 3.8
Compared to 221 running shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

We're disappointed that the durability issues we saw with the Adizero Boston 11 persist in the Boston 12, which led us to give it a low score of 1 out of 5.

It's clear to us that Adidas has the technology and know-how to create a thin-yet-robust upper for the Boston 13, similar to what Nike achieved with the Alphafly 2. We can only hope they step up their game for the next release.

Adidas Adizero Boston 12 Toebox durability
Test results
Adizero Boston 12 1
Average 2.3
Compared to 155 running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

To our pleasant surprise, the heel padding proved to be significantly more resilient than we anticipated, especially after the disappointment of our previous Dremel test.

In our usual procedure of applying 3.2N for four seconds at a brisk 10,000 RPM, the Boston 12 stood impressively, demonstrating a commendable level of durability in the heel counter. And the comparison against the Hoka Gaviota 4 speaks for itself. 

Adidas Adizero Boston 12 Heel padding durability
Test results
Adizero Boston 12 3
Average 3.2
Compared to 151 running shoes
Number of shoes
1
Heel padding durability
5

Outsole hardness

Undoubtedly, the most applauded feature of the Boston 12's predecessor was its outsole, a durable-yet-grippy rubber that only a select few shoes can claim to have as of today.

With the v12, we observed some changes. Given the exceptional durability of the Boston 11, Adidas trusted Continental to create a softer compound for the Boston 12 that we measured at 79.8 HC—8% softer than v11 . It's a clear attempt to enhance an already high-performing outsole, and it worked wonders.

Adidas Adizero Boston 12 Outsole hardness
Test results
Adizero Boston 12 79.8 HC
Average 80.4 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 272 running shoes
Number of shoes
54.9 HC
Outsole hardness
92.8 HC

Outsole durability

But how can we be certain that the durability remains incredibly impressive? It's because we put it through rigorous testing in our lab. We used our Dremel test once more, this time to gauge the amount of rubber that vanished post-abrasion.

The final outcome was nothing short of astounding: despite its softer formulation, the Dremel only succeeded in creating a mere 0.7 mm dent, which is less than the 0.74 mm measured on the Boston 11.

This result shines brightly when compared to the average shoe, affirming the extraordinary durability of the Boston 12.

Adidas Adizero Boston 12 Outsole durability
Test results
Adizero Boston 12 0.7 mm
Average 0.9 mm
Compared to 133 running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

A common critique of the revamped Boston series—after its longstanding status as a low-stack shoe—has been the increased weight. We fondly remember the nimble and lightweight models like the Boston 9, and the latest two versions felt significantly bulkier in comparison.

Adidas Adizero Boston 12 outsole

There are 2 possible weight-saving options for any outsole:

  • Minimize the thickness of the rubber.
  • Increase the amount of exposed foam.

Adidas chose the first path, decreasing the outsole thickness from 3.3 mm to 2.8 mm in this version.

We've found this approach particularly effective, and in light of the exceptional durability exhibited by the Boston 12, we anticipate that Adidas might reduce the thickness even more in the next iteration.

Adidas Adizero Boston 12 Outsole thickness
Test results
Adizero Boston 12 2.8 mm
Average 3.2 mm
Compared to 291 running shoes
Number of shoes
0.0 mm
Outsole thickness
6.6 mm

Weight

As we just mentioned, Adidas truly excelled in this area with the Boston 12. The shoe now comfortably falls under the 10 oz threshold, weighing in at only 9.2 oz or 261g. This makes it lighter than the average running shoe!

Now, we believe this true Boston model is ready to take on its peers in the arena of lightweight tempo trainers like the crowd-favorite Saucony Endorphin Speed 3.

Adidas Adizero Boston 12 Weight
Test results
Adizero Boston 12 9.21 oz (261g)
Average 9.38 oz (266g)
Compared to 292 running shoes
Number of shoes
5.26 oz (149g)
Weight
12.56 oz (356g)

Cushioning

Heel stack

The moment we received the shoe in the lab, we found the Boston 12 noticeably sleeker than its predecessor. However, nothing beats the precision of a caliper for an accurate measurement.

The heel, at 34.5 mm, offers 4.6 mm less Lightstrike EVA foam.

This adjustment by the German brand won our approval, echoing the sentiments of many runners who felt the version 11 was bulky and had excess foam in the heel for what should be a speed-focused running shoe.

Adidas Adizero Boston 12 Heel stack
Test results
Adizero Boston 12 34.5 mm
Average 33.6 mm
Compared to 291 running shoes
Number of shoes
7.6 mm
Heel stack
42.7 mm

Forefoot stack

On the other hand, the forefoot thickness remains almost unchanged, clocking in at 28.4 mm. This measurement is 0.9 mm less than the previous model's, making it nearly identical.

Adidas Adizero Boston 12 Forefoot stack
Test results
Adizero Boston 12 28.4 mm
Average 24.9 mm
Compared to 291 running shoes
Number of shoes
7.6 mm
Forefoot stack
35.8 mm

Drop

The 6.1-mm heel-to-toe drop between the heel and forefoot is significantly benefits midfoot and forefoot strikers. And the shoe comes packed with even more of the premium Lightstrike Pro foam in the forefoot area than ever before.

However, those with an extreme heel-strike pattern might find the previous model more suited for that foot strike.

Adidas Adizero Boston 12 Drop
Test results
Adizero Boston 12 6.1 mm
Average 8.7 mm
Compared to 291 running shoes
Number of shoes
-0.8 mm
Drop
16.1 mm

Insole thickness

In the Boston 12, the insole is exactly what we expect from a speed trainer. At 3.8 mm, we found it a tad thinner than what you'd find in a daily trainer, yet it's comfortably capable of supporting long runs.

Adidas Adizero Boston 12 Insole thickness
Test results
Adizero Boston 12 3.8 mm
Average 4.5 mm
Compared to 287 running shoes
Number of shoes
1.5 mm
Insole thickness
7.3 mm

Midsole softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

Adidas has, for a while, been incorporating the less impressive Lightstrike EVA foam in many of its training shoes. We all found it a bit of a disappointment. However, things are finally changing.

Now, enter the new Lightstrike 2.0. Yes, it's still an EVA-based foam, but it's a whole lot lighter and feels far more bouncier underfoot.

While it's crucial to note that it's not the softest foam on the market—we clocked it at 24.0 HA—it's certainly a marked improvement over the first-generation Lightstrike.

Adidas Adizero Boston 12 Midsole softness
Test results
Adizero Boston 12 24.0 HA
Average 21.4 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 219 running shoes
Number of shoes
8.5 HA
Midsole softness (soft to firm)
41.5 HA

Secondary foam softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

The real standout in this shoe is the TPEE-based Lightstrike Pro. We've delved into this world-class foam in our advanced guide about midsoles. It boasts phenomenal energy return, remarkable durability, and an optimal balance in softness, which we gauged at 18.5 HA in the lab.

This is why the shoe feels notably better underfoot than its predecessors. It packs more Lightstrike Pro than ever, and in a softer formulation, too. Compared to the previous version—the v11, which we measured at 23.5 HA—the improvement is palpable.

Adidas Adizero Boston 12 Secondary foam softness
Test results
Adizero Boston 12 18.5 HA
Average 25.2 HA
We use an average of four tests. The photo shows one of those tests.

Midsole softness in cold

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.
Adidas Adizero Boston 12 Midsole softness in cold

Difference in midsole softness in cold

EVA midsoles tend to get really firm in cold temperatures, and the Lightstrike 2.0 foam follows this pattern. We measured it at 30.0 HA after a 20-minute nap in our freezer, and we also felt it firmer underfoot.

This 25% firmness increase is a standard result, yet it signifies an upgrade from the first-generation Lightstrike foam.

Adidas Adizero Boston 12 Midsole softness in cold
Test results
Adizero Boston 12 25%
Average 25.6%
Compared to 218 running shoes
Number of shoes
0%
Difference in midsole softness in cold
100%

Stability

At 269.4 mm, it matches quite remarkably with Adidas' size charts. This is a 100% a true-to-size shoe.

Lateral stability test

We firmly believe that the Boston remains an impressively stable shoe, especially considering its elevated height.

Through our static tests and fast-paced test runs, we consistently experienced a reassuring sense of balance.

Torsional rigidity

When we applied torsional force to the shoe, it readily resisted twisting and we rated it at 4/5.

Despite this, the Boston 12 displays slightly more flexibility than its predecessor, and that's a positive change. The reason for this lies in the shoe's Energyrods. The current model uses full-length fiberglass Energyrods, which are not quite as rigid as the combination of a carbon-fiber plate and Energyrods featured in the previous model.

Test results
Adizero Boston 12 4
Average 3.2
Compared to 270 running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

In the shoe's heel, we discovered a counter stiffness more akin to that of racing shoes. It didn't resist our applied force at all. On a scale where 5 is the stiffest, we'd rate this a mere 1.

Heel strikers might have preferred a rating of 2 or 3 out of 5 to improve stability. But, as we've already mentioned, Adidas seems to have designed this shoe with midfoot or forefoot strikers in mind.

Test results
Adizero Boston 12 1
Average 2.8
Compared to 254 running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width in the forefoot

And here's more evidence of this focus. We measured the landing platform in the forefoot of this shoe at a whopping 118.2 mm, providing significant stability for midfoot or forefoot strikers. 

Take the Boston 11, for example. We measured its landing platform at 109.3 mm, which is narrower than most shoes. However, this 12th edition is among the widest shoes we've ever measured.

Adidas Adizero Boston 12 Midsole width in the forefoot
Test results
Adizero Boston 12 118.2 mm
Average 113.6 mm
Compared to 292 running shoes
Number of shoes
100.5 mm
Midsole width in the forefoot
126.5 mm

Midsole width in the heel

In contrast, the heel remains moderately narrow in true Adidas style. We measured it at 86.0 mm.

Adidas Adizero Boston 12 Midsole width in the heel
Test results
Adizero Boston 12 86.0 mm
Average 90.5 mm
Compared to 292 running shoes
Number of shoes
74.9 mm
Midsole width in the heel
106.6 mm

Flexibility

Stiffness

We've mentioned before that the Boston 12 is more flexible, thanks to the swap from a carbon plate to the full-length fiberglass Energyrods. Now, we've got the solid proof for you.

In our test to bend the shoe 90-degrees, it took less muscle force (26.7N) with the Boston 12 than with the average running shoe. This is a complete turnaround from the previous model and a refreshing and welcome change than makes the shoe way more versatile.

Test results
Adizero Boston 12 26.7N
Average 29.3N
We use an average of four tests. The video shows one of those tests.
Compared to 274 running shoes
Number of shoes
2.2N
Stiffness
94.4N

Difference in stiffness in cold

And no worries at all when it comes to chilly weather. Our measurement shows we only need a force of 33.3N to bend the Boston 12 to 90 degrees. That's even less than what it took to flex the Boston 11 in room-temperature conditions!

The gap between the two measurements shows an impressive 24.6% change. It's a monumental step up from last year's model, as it suffered a 42.0% increase in stiffness.

Undeniably, the introduction of the new Lightstrike 2.0 EVA foam played a substantial role in this success.

Test results
Adizero Boston 12 24.6%
Average 36.3%
Compared to 274 running shoes
Number of shoes
0%
Difference in stiffness in cold
148%

Size and fit

Internal length

At 269.4 mm, it matches quite remarkably with Adidas' size charts. This is a 100% a true-to-size shoe.

Adidas Adizero Boston 12 Internal length
Test results
Adizero Boston 12 269.4 mm
Average 269.1 mm
Compared to 155 running shoes
Number of shoes
259.9 mm
Internal length
280.4 mm

Toebox width at the widest part

The overall agreement is that the revamped Boston saga works wonderfully for those of us with wide feet. This fact was confirmed the moment we received the shoe in the lab and tried it on.

But why not back it up with exact measurements, right? Armed with our caliper, we noted a more generous width than average—a substantial 101.9 mm in the broadest part of the upper.

Adidas Adizero Boston 12 Toebox width at the widest part
Test results
Adizero Boston 12 101.9 mm
Average 98.3 mm
Compared to 292 running shoes
Number of shoes
89.5 mm
Toebox width at the widest part
109.1 mm

Toebox width at the big toe

The same generous sizing continues in the big toe area. With a width of 78.2 mm, this shoe offers plenty of space for the toes of nearly every type of foot.

Adidas Adizero Boston 12 Toebox width at the big toe
Test results
Adizero Boston 12 78.2 mm
Average 78.0 mm
Compared to 166 running shoes
Number of shoes
60.4 mm
Toebox width at the big toe
92.5 mm

Tongue: gusset type

In our lab test of the Boston 11, we liked its fully-gusseted tongue, though if we were designing the shoe, we'd have opted for a semi-gusseted design.

Now, Adidas has dismissed the fully-gusseted tongue, which might sound like good news. But they've replaced it with a non-gusseted one. That's a real bummer, especially for a training shoe that sets you back £170.

Adidas Adizero Boston 12 Tongue: gusset type
Test results
Adizero Boston 12 None

Comfort

Tongue padding

Adidas has really taken a weight-loss approach with the Boston 12, and it seems like the shoe's tongue got a bit too much of the slimming treatment. Now it's half the usual thickness in a training shoe.

We're not big fans of this particular change—the tongue really feels one of the few steps back from the previous models.

Adidas Adizero Boston 12 Tongue padding
Test results
Adizero Boston 12 2.9 mm
Average 5.6 mm
Compared to 289 running shoes
Number of shoes
0.5 mm
Tongue padding
14.2 mm

Heel tab

Keeping up with Adidas' cool design trends that started with the Adizero Adios Pro 3, the Boston 12 sports the same slick, flap-like pull tab on the heel.

Adidas Adizero Boston 12 flap

We've got to say, we're totally digging this look—it's like having the rear wing of an F1 car right on our heels!

Adidas Adizero Boston 12 Heel tab
Test results
Adizero Boston 12 Pull tab

Removable insole

Whether you prefer to use our own orthotics or a different shoe insole, it's no issue, because the Boston 12's insole isn't glued down at all.

Adidas Adizero Boston 12 Removable insole
Test results
Adizero Boston 12 Yes

Misc

Reflective elements

Once again, Adidas seems to have overlooked the needs of night runners. The shoe doesn't have a single reflective element, which is a disappointment.

Adidas Adizero Boston 12 Reflective elements
Test results
Adizero Boston 12 No