Mizuno is on a roll in 2025, and their third major launch of the year keeps the momentum going strong. After introducing the lively Neo Vista 2 and the smoothly refined Wave Rider 29, the brand now shifts gears into max cushion territory with the debut of the Wave Sky 9.
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Looks
The color profile of the Mizuno Wave Sky 9 sorta mirrors the Wave Rider 29 I tested earlier, featuring a dark upper paired with a clean white midsole. What sets it apart is the splash of color on the logos and above the outer midsole that separates the two—giving it a pop of personality without going overboard. It’s a fun, simple design, and arguably the most eye-catching of the four available colorways.
Construction and Fit
Mizuno has been on a solid trajectory in recent years, showing a renewed commitment to delivering dependable, well-thought-out running shoes backed by real tech and smart product strategy. The Wave Rider 29 proved how dialed-in a legacy trainer can feel, and the Neo Vista 1 and 2 turned heads with its energetic ride and modern profile. Naturally, that built up some lofty expectations (pun intended) for the overhauled Wave Sky 9.
As a high-stack daily trainer, the Wave Sky 9 finally goes all into plushy comfort with a 44mm heel stack height and a dual-layer foam setup of Mizuno Enerzy NXT -a supercritical EVA version on the top and a standard EVA on the bottom. A Foam Wave design adds some essential structure to what would otherwise be a wobbly ride at this height. While it’s hard to call any shoe nearing 45mm stack as “stable,” this one comes impressively close, offering a surprisingly steady feel due to the Foam Wave and a wider base.
That said, the shoe is definitely on the heavier side and can’t really hide it—I felt that weight, especially when trying to pick up the pace. But for what it’s built for—recovery days and steady, easy miles—it hits the mark. The plush underfoot feel reminds me a lot of the Puma Magnify Nitro: soft, forgiving, and geared for comfort over speed.
Specs
- Heel Stack Height: 44mm/38mm
- Drop: 6mm
- Weight: 10oz (M9)
Upper
The stretch woven upper on the Wave Sky 9 is sleek and relatively breathable (though could be improved), with a construction that looks as good as it performs—at least on cooler days. During a few mid-summer test runs, it ran a bit warm, though perhaps that’s not entirely unexpected for a shoe with this much material and padding.
Despite Mizuno’s “stretch woven” label, the upper felt a bit more structured than anticipated, especially in the toe box. It came across as somewhat rigid and slightly snug. The upper and tongue do a solid job of locking down the foot, but I found the overall fit more constricting than I’d expected from something marketed as stretchy.
Still, in true Wave Sky 9 fashion, the heel and tongue are plush and comfortable—adding to that overall cushy, high-mileage vibe.
Midsole
The midsole of the Wave Sky 9 leans heavily into plushness—this one’s built for runners who enjoy that soft, marshmallowy compression underfoot. With the dual-layer combo of Mizuno Enerzy NXT, the shoe delivers serious cushioning that soaks up impact mile after mile.
That said, my first few runs had me feeling that it’s not the most responsive ride. And that’s not a knock—it’s just the nature of this kind of max-stacked design. However, it seemed to become more dialed in as I wore it more (perhaps my legs were tired during those first few runs – or it hit its stride, I don’t know). Either way, I liked this more with each run.
This still isn’t the shoe I’ve been reaching for when trying to push the pace or add a pop to my stride. Instead, it shined on days when comfort was the priority and I wanted to log some easy or recovery miles. It’s a plush cruiser through and through—no complaints if you know what you’re getting.
Outsole
The outsole on the Wave Sky 9 gets an update with Mizuno’s full-length X10 carbon rubber, designed for durability and longer wear. The rubber is noticeably thick in high-impact areas, while some exposed midsole helps keep the overall weight in check.
This redesign also seems aimed at adding a touch of stiffness to an otherwise plush and flexible shoe—likely in hopes of creating a bit more rebound. While I wouldn’t call it particularly responsive or energetic, I do appreciate the attempt to balance cushion with a bit of structure. Traction-wise, it’s plenty grippy for the types of easy, steady runs this shoe is made for.
Conclusion
There’s a lot to like about the Mizuno Wave Sky 9 if you’re in the market for a true max-cushioned experience. The plush, comfortable midsole, and a solidly stable ride, delivers exactly what you’d hope for on recovery days or long, easy miles. Just be aware that the upper—while sleek and secure—may feel a bit rigid for some, so it’s worth trying on at your local running store if possible.
Go into this shoe with the right expectations—it’s built for comfort, not speed—and you’ll likely come away impressed. It’s not a PR-chaser, but for logging relaxed, cushioned miles, the Wave Sky 9 does its job well.
