Mizuno Wave Sky 9 Review
By Bach Pham
Mizuno Wave Sky 9Price: $179.95 at Running Warehouse
Weight: 10.3 oz, 292 g (men's size 9), 8.6 oz, 244 g (women's size 8)
Stack Height: 44 mm heel / 38 mm forefoot
Drop: 6 mm
Shoe Purpose: Daily Trainer
Pros: Fit comfortable, tank-like build
Cons: Very stiff and firm ride
RUNNING SHOE SUMMARY
The Mizuno Wave Sky 9 features a healthy 44mm stack height in the heel, pushing it truly up into the top end of trainers numbers-wise. The shoe features MIZUNO ENERZY NXT (Nitrogen Infused EVA) as the core engine to the shoe with a layer of Enerzy for rigidity underneath it, a super tough X10 outsole, a comfortable woven upper. The shoe is best for runners who want a highly stiff ride, cushioned ride for very easy runs or walking.
SIMILAR SHOES: Diadora Cellula 2
PAST MODEL: Mizuno Wave Sky 8
FIT
(To learn how a shoe should fit, check out our full podcast on fit by Matt Klein.)
Bach: The Mizuno Wave Sky 9 has a bit of a funny fit. It has a very tapered toebox with a lower volume fit that is bordering on the snug side. The midfoot and heel open up with more volume. It wasn't a bad fit in the forefoot for me, but noticeably less volume and a slightly tighter space. The heel is a bit loose for me. I didn't fear heel slipping, but it didn't totally provide a locked-in feel with the whole shoe. I tried heel locking, but that didn't quite pull it in enough and the laces are also on the shorter side in general. I think the whole shoe could just fit a little better for my foot all-around, and I don't think sizing up or down would fix it due to the toebox.
Typical Size: Men's US Size 9.5
Shoes that have fit Bach well:
Nike Pegasus 40, Saucony Guide 17, Mizuno Wave Inspire 19, Saucony
Endorphin Speed 3, Nike Structure 25
Shoes that have fit snug: Hoka Arahi 7, Asics Kayano 30, Puma Electrify Nitro, Brooks Hyperion, Hoka Clifton 9 GTX
Shoes that have fit large: Hoka Gaviota 5, Reebok Floatride Energy X
Doctors of Running Checklist
Is This a Good Shoe for Walking: Yes
Is This a Good Shoe for Standing: Yes
Is the Forefoot Flexible: No
How Flexible is the Shoe: None
Is This a Good Heel Bevel: No
Recommended for Haglunds: No
Is This Shoe Orthotic Friendly: Yes
Recommended for Sockless: Yes
Durability Expectation: High
PERFORMANCE
Bach: The Mizuno Wave Sky 9 has always been a bit of a funky max cushion shoe for our team. The midsole in the latest edition features a big wedge of Enerzy NXT, a supercritical EVA. Below the NXT is their regular Enerzy midsole to help stabilize landings. Out of box, the shoe felt very disjointed and a bit stiff. The two foams didn't quite feel like they wanted to work together. The NXT initially is kind of soft and the Enerzy kind of firm and the shoe being stiff kind of didn't really mesh super well. As the midsoles broke in after a few runs and started melding together better, the shoe's identity starts coming across. The Wave Sky 9 after 20 miles now runs kind of middle of the road. Moderately cushioned, leaning firmer, with a lot of stiffness still. The rocker is not super prominent feeling, even though it looks very similar to the Diadora Cellula 2 I reviewed recently. I do run midfoot forward, but the heel doesn't clear as cleanly, leaving a slightly less smooth ride. I actually liked the shoe best when I pushed a little harder, but it's not really a shoe for workouts due to its weight. It does fine at easy paces, but doesn't make me really want to take it longer than a regular daily run due to the slightly clunkiness of the ride and the weight.
The shoe kind of goes on a list of max cushion shoes I've tested where I feel like me being a lighter runner, I'm not getting the most out of the shoe. When I really pushed the midsole into the ground, I got the most out of its responsiveness. It isn't like the Diadora Cellula 2 which felt lighter and easy to turnover on the run or like its stability peer the Wave Horizon which is much firmer, but transitions smoother. If you really impact the ground aggressively, you might really like the Wave Sky, but if you are lighter on your feet you might not get the most out of this edition.
The outsole is plentiful, durable, and trusty on wet roads. It's also fine for walking, but with the overall fit I do have other models for myself I'd take over this. If the Wave Sky 9 suits your feet's needs though the midsole is comfortable enough for all day use for sure.
All that said, if you have been a Wave Sky user in the past, I do feel like this is the best version of the shoe so far. It's by far the most cushioned and lightest Sky yet, with a very similar fit as past versions. This is also going to be a decent all-day walking shoe for those who want a softer step.
STABILITY
(Learn more about stability in our full guide)
Bach: The Wave Sky 9 despite having a lot of characteristics that make other max cushion shoes stable, is pretty neutral until the shoe breaks in and firms up a little bit. The wide base and sole flaring helps then. I do think the loose heel for me makes the shoe feel less stable, and adds some foot movement that slightly irritated my flat feet. You really want to make sure the fit is very good on your end when trying the Wave Sky 9 on foot.
Thoughts as a Runner: A Thousand (Ways to Mess Up Your) Miles
By Bach Pham
We get so many emails at Doctors of Running about different needs. So much so that it actually is very rare to answer emails the same way twice. We are each unique individuals with a multitude of features that makes us very individual. Even within our team we have tons of differences and specific items that we each prefer, from midsole feel to fit to outsole needs (MATT) to stability levels. There are a lot of different combinations of things that each of us want and prefer, which is why it can be really hard to say a shoe is bad. Just because the Wave Sky 9 didn't totally work for me doesn't mean its combination of a lower volume toebox with wider heel might be the Goldilocks combination someone else needs. There are certainly some shoes each year that seem to find that magic combination that hits a large swath of runners, but even then each person will have their reasons why they like the shoe and some faults that others might not find. We hope you take our reviews as just information to help you think about what you want in a shoe when you're trying it on and deciding if it fits your needs. Don't let a bad review deter you from a shoe that just might match perfectly up to you, even if you're the only one. The On Cloudboom Max is a great example of a shoe this year that absolutely divided our team. Half felt it was absolutely the worst thing they have put on their feet all year and the other half consider it their favorite recovery shoe of 2025. You just never know until you try.
RECOMMENDATIONS
Bach: The Wave Sky 9 features some nice changes over past editions, but remains a puzzle for me when it comes to Mizuno. With so much innovation and quality shoes in the lineup like the Neo Vista, I think its well past time to reconsider the use of their Wave system in this series and consider trying to maximize their midsoles which are now becoming standout competitors in the market. I think Mizuno can deliver a really solid, simple max cushion shoe that is priced well under the Neo Vista ($200) for those who want a comfortable high stacked option from the brand. I think with so much outsole on the shoe to provide rigidity underneath, delivering a full length Enerzy NXT may bring out the best in the shoe rather than the complicated Wave system in place.
Some addition changes for a broader audience I think would include widening the toebox to accommodate more runners, tightening up the heel fit to be more blended with the rest of the shoe, adding slightly longer lacing, and continuing to smoothen the heel out.
WHO IS THIS SHOE FOR?
Bach: The Wave Sky 9 is best for runners who are aggressive on their feet to get the most out of the shoe's midsole. The Wave Sky 9 is a daily driver that will clock tons of miles for you if the shoe meets your needs. Checking fit is critical to make sure the Wave Sky 9 matches up with your needs. Runners who are light on their feet might want to consider some of Mizuno's other dynamic options that have come out this year, including the Neo Vista 2.
GRADES
Bach
Fit: C+ (Heel fit and short lacing leaves a slightly loose fit that impacts the ride of the shoe for me)
Performance: B- (Took a little breaking in, but once broken in provides a modestly cushioned ride)
Stability: B- (Heel security and slightly unstable initial miles)
Value: B+ (Top end pricey, but huge durability from the midsole and outsole I expect)
Personal: C (I don't think it's a bad shoe, but there's just so many in this category that I have a hard time putting it high on my list, especially with )
Overall Design: B-
SHOP | SUPPORT DORMizuno Wave Sky 9Price: $179.95 at Running Warehouse
Shop Men | Shop Women
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FURTHER READING
Diadora's max cushion trainer.
Find all Shoe Reviews at Doctors of Running here.
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NEXT: Diadora Cellula 2
