The Y-3 Ultraboost 5 puts an elevated spin on running shoes. It features a range of subtle yet sophisticated additions to an iconic silhouette, including an all-new TPU heel cage with an embossed Yohji Yamamoto signature and an updated lace cage. An adidas PRIMEKNIT upper, a BOOST midsole and a Continental Rubber outsole give these trainers serious traction and cushioning.
The Y-3 Ultraboost 5 puts an elevated spin on running shoes. It features a range of subtle yet sophisticated additions to an iconic silhouette, including an all-new TPU heel cage with an embossed Yohji Yamamoto signature and an updated lace cage. An adidas PRIMEKNIT upper, a BOOST midsole and a Continental Rubber outsole give these trainers serious traction and cushioning.
The Y-3 Ultraboost 5 puts an elevated spin on running shoes. It features a range of subtle yet sophisticated additions to an iconic silhouette, including an all-new TPU heel cage with an embossed Yohji Yamamoto signature and an updated lace cage. An adidas PRIMEKNIT upper, a BOOST midsole and a Continental Rubber outsole give these trainers serious traction and cushioning.
The Y-3 Ultraboost 5 puts an elevated spin on running shoes. It features a range of subtle yet sophisticated additions to an iconic silhouette, including an all-new TPU heel cage with an embossed Yohji Yamamoto signature and an updated lace cage. An adidas PRIMEKNIT upper, a BOOST midsole and a Continental Rubber outsole give these trainers serious traction and cushioning.
Last updated at 03/21/2026 15:45:35
Y-3 UltraBOOST 5 Core Black/ Core Black/ Off-White EUR 42
Delivery between Tue – Fri $78.96
adidas Y-3 UltraBoost 5 'Black' | Men's Size 8.5
Delivery between 23–30 Mar $25
originally posted on roadrunnersports.com
It has been over a decade since a last ran on Adidas cause I always found their fit too narrow. I tried the UB 21 and surprisingly it fit me well. The Prime Blue material is top notch and good quality and stretchy. One of the draws to me for trying this shoe was aesthetics and in my opinion the best looking running shoe out right now. However, when running on it it was a different story. I had considerable heel slip more on my right than left heel. I felt the weight of the shoe when picking up the pace to my normal zone 2 pace and when picking it up to marathon and tempo pace the boost cushioning feels flat and dead. The bounce goes away and I didn't feel any responsiveness or pop from the plate on the bottom. It actually felt the opposite like I was fighting the ... MoreIt has been over a decade since a last ran on Adidas cause I always found their fit too narrow. I tried the UB 21 and surprisingly it fit me well. The Prime Blue material is top notch and good quality and stretchy. One of the draws to me for trying this shoe was aesthetics and in my opinion the best looking running shoe out right now. However, when running on it it was a different story. I had considerable heel slip more on my right than left heel. I felt the weight of the shoe when picking up the pace to my normal zone 2 pace and when picking it up to marathon and tempo pace the boost cushioning feels flat and dead. The bounce goes away and I didn't feel any responsiveness or pop from the plate on the bottom. It actually felt the opposite like I was fighting the shoe just to get a quicker turnover. It also felt clunky. When at jogging pace the shoes felt fine and could feel the boost cushioning. Overall not the cushioned daily trainer I expected and this version has leaned more towards the casual athleisure category. This is a great walker/jogger but as a shoe part of a rotation for training it's a hard pass. Really wanted to like this shoe but for what I bought it for it's a big disappointment and will be returning it.
originally posted on finishline.com
I really liked the Ultraboost 20s and bought 2 pairs of the Ultraboost 21 to add in my rotation. I work out 4-5 days a week, doing cardio and weights. And these feel really good on my feet. I am not an avid runner, but as advertised, the additional boost feels more responsive and more cushioned. If you liked the Ultraboost 20s, you'll like the upgrade on the Ultraboost 21s. I am a heavy set guy, I've lost over 60 lbs in the last year, and have put my Ultraboosts through the test...
originally posted on Academy Sports + Outdoors
The fit is almost tight enough not to need any laces. I havent tried the size up. I'm normally a 8.5 on Nike but this is snug fit. The archilles tendon has two plastics to hold the shoe in and its tight if you use any cross training or side movements. Just good for running. Been running on a treadmill and not used outdoor.The top lip of my left shoe flips back and doesnt look all that great when i wear it. If only they moved the adidas label just a bit higher so it wont flip back .
Y-3 UltraBOOST 5 Core Black/ Core Black/ Off-White EUR 42
Delivery between Tue – Fri $78.96
adidas Y-3 UltraBoost 5 'Black' | Men's Size 8.5
Delivery between 23–30 Mar $25
It has been over a decade since a last ran on Adidas cause I always found their fit too narrow. I tried the UB 21 and surprisingly it fit me well. The Prime Blue material is top notch and good quality and stretchy. One of the draws to me for trying this shoe was aesthetics and in my opinion the best looking running shoe out right now. However, when running on it it was a different story. I had considerable heel slip more on my right than left heel. I felt the weight of the shoe when picking up the pace to my normal zone 2 pace and when picking it up to marathon and tempo pace the boost cushioning feels flat and dead. The bounce goes away and I didn't feel any responsiveness or pop from the plate on the bottom. It actually felt the opposite like I was fighting the ... MoreIt has been over a decade since a last ran on Adidas cause I always found their fit too narrow. I tried the UB 21 and surprisingly it fit me well. The Prime Blue material is top notch and good quality and stretchy. One of the draws to me for trying this shoe was aesthetics and in my opinion the best looking running shoe out right now. However, when running on it it was a different story. I had considerable heel slip more on my right than left heel. I felt the weight of the shoe when picking up the pace to my normal zone 2 pace and when picking it up to marathon and tempo pace the boost cushioning feels flat and dead. The bounce goes away and I didn't feel any responsiveness or pop from the plate on the bottom. It actually felt the opposite like I was fighting the shoe just to get a quicker turnover. It also felt clunky. When at jogging pace the shoes felt fine and could feel the boost cushioning. Overall not the cushioned daily trainer I expected and this version has leaned more towards the casual athleisure category. This is a great walker/jogger but as a shoe part of a rotation for training it's a hard pass. Really wanted to like this shoe but for what I bought it for it's a big disappointment and will be returning it.
I really liked the Ultraboost 20s and bought 2 pairs of the Ultraboost 21 to add in my rotation. I work out 4-5 days a week, doing cardio and weights. And these feel really good on my feet. I am not an avid runner, but as advertised, the additional boost feels more responsive and more cushioned. If you liked the Ultraboost 20s, you'll like the upgrade on the Ultraboost 21s. I am a heavy set guy, I've lost over 60 lbs in the last year, and have put my Ultraboosts through the test...
The fit is almost tight enough not to need any laces. I havent tried the size up. I'm normally a 8.5 on Nike but this is snug fit. The archilles tendon has two plastics to hold the shoe in and its tight if you use any cross training or side movements. Just good for running. Been running on a treadmill and not used outdoor.The top lip of my left shoe flips back and doesnt look all that great when i wear it. If only they moved the adidas label just a bit higher so it wont flip back .
Somehow the ultraboost keeps getting better. The 19 and 20, while less appealing to the eye than previous models were much more comfortable, something we couldn't imagine prior to their release due to the comfort of the previous UB silhouettes. You get that soft reactionary cushion boost is known for with added stability and a good look in these. They still fit like a glove, but give you a little more wiggle room to keep your toes straight and nails healthy. You owe it to yourself to try them out whether you are a committed runner or on that casual lifestyle steez.
I run from 1 to 1.5 hours daily and have for about 50 years. I buy two pairs of shoes at a time, rotate them daily, and replace them with another pair in about three months. I have worn Adidas exclusively for about 30 years. The Ultra Boost 21 is the most uncomfortable Adidas shoe I have worn. I blame the thick plastic "plates" housing the eyelets through which the shoelaces run. With little effort, the edges of the plates could be filed to a knife's blade sharpness. They are that thick. They are so thick that they inflexible, probably by design. And, other than hold the eyelets for the shoelaces, their only function seems to be to cause the upper parts of my feet to hurt. These shoes are miserable to wear. I am stubborn, so I am going to wear them for three months. ... MoreI run from 1 to 1.5 hours daily and have for about 50 years. I buy two pairs of shoes at a time, rotate them daily, and replace them with another pair in about three months. I have worn Adidas exclusively for about 30 years. The Ultra Boost 21 is the most uncomfortable Adidas shoe I have worn. I blame the thick plastic "plates" housing the eyelets through which the shoelaces run. With little effort, the edges of the plates could be filed to a knife's blade sharpness. They are that thick. They are so thick that they inflexible, probably by design. And, other than hold the eyelets for the shoelaces, their only function seems to be to cause the upper parts of my feet to hurt. These shoes are miserable to wear. I am stubborn, so I am going to wear them for three months. I will then use the plastic plates to scrape paint off walls. I gave the shoe two stars because everything but the plastic plates is okay. I do not recommend this shoe.
I purchased the 21 Boost based on previous experience with the 20's. While these are very different in looks, they provide the same comfort. I'm not a runner, but the cushion in these really help alleviate back pain during long time use. The color way is amazing, I'm a fan of the small details in the upper of the shoe with small touches of the accent color throughout. If you're looking to buy a pair but find yourself on the fence, make the jump. Your feet and back will thank you and you'll get plenty of compliments as an added bonus.
This is a very functional shoe and looks great. Got this for walking and light jogs and have to say it is thee most comfortable shoe I’ve worn. My only frame of reference are under armour running shoes and various lifestyle trainers so you don’t have to take my word for it.I went half size up, first wear was a little tight but after wearing a few times I wish I had gone true to size. That primeknit makes them so easy to break in.Very comfy and supportive, when my feet start to get tired I can sort of adjust my stepping and feels like I’m walking on clouds. Basically all parts of the shoe are comfortable so it doesn’t matter if you’re heel stepping, toe stepping, side stepping -this shoe with support you and bounce back.
I'm heavier set with a wider foot and this has the perfect balance of cushion and support, plus the upper just moulds to my foot shape for an ideal fit. Genuinely would forget I had the shoes on if not for the soft feeling underfoot. I found to be true to size, and wear the same size in these as I did my ub 19s. Personally I prefer th3se compared to my old ubs. One word of warning, even though these have more boost than the last version they're actually a little bit firmer, which I like for comfortable stability, but if your preference is squishier and you expect it to be softer than older versions you may be disappointed.
I'm a recreational runner, some trail and some road. I very much enjoyed the UB 19's and decided to skip a version and go fro the 21. The magic is still there in the springy, comfy road feel and still good to go on hardback trail. The change in the upper Wass the downfall and the reason for 3 stars instead 5, the toe box is not as roomy and really punished my big toes. If you can wear the Nike Peg 37 without issue, this will likely be ok for you. I am also a big fan of the Peg, but similarly the latest version is to tight on the big toe for me. Have great run, there is never a bad one.
We had bought two pair of this item one for my wife and one for myself . The shoe is so uncomfortable that it grips your foot and makes it too tight and you are not able to keep it on. We bought it as we thought it would be better then the previous one but no its useless and not worth buying. The worst upon that is the customer care who do not give any s..t about customers comfort and health. We being both over 50 found it so uncomfortable that we are still happy with our old shoes. A total waste of money.
