Mizuno announced Thursday the launch of the Mizuno Pro S-4 iron, the newest addition to the Signature Series lineup. The Pro S-4 is now the most forgiving model in the series to date, developed for players seeking a refined headstyle and the precision and forged feel of a Mizuno Pro iron. The S-4 produces a higher-launching ball flight thanks to the more forgiving player’s cavity-back profile.
With the S-4 model, Mizuno has redesigned the cavity structure to feature a softer, curved shaping throughout the back of the iron. This helps deliver a more refined appearance, but also strategically distributes mass in the head to enhance stability and forgiveness. The irons also feature an increased offset design and wider sole that allows golfers to launch the ball on mishits. The offset progresses throughout the set, allowing for greater forgiveness with the longer irons.
Along with the progressive offset, the topline design of the S-4s also features progressive shaping, with the shorter clubs featuring a more compact profile that delivers precision and control, compared to the longer irons, which are thicker for better performance.
The S-4s heads are forged from a single billet of 1025E Pure Select Mild Carbon Steel using Mizuno’s patented “Grain Flow Forged HD” process and enhanced by a copper underlay to produce a soft and responsive feel, while delivering precise feedback at impact. The copper underlay is used to dampen vibration for an even more refined sensation.
Engineered to improve turf interaction, Mizuno’s S-4 irons employ a triple-cut sole. The design allows the club to move efficiently through a variety of conditions while helping maintain speed and consistency through impact.
Finally, S-4 irons use strategically engineered sound and vibration tuning, otherwise known as Mizuno’s “Harmonic Impact Technology” (H.I.T.), which creates a solid, satisfying sound and feel.
With the addition of the S-4, the Mizuno Signature Series is the company’s broadest performance range. The lineup began with the Mizuno Pro S-3, focused on tour-driven iron development, offering a modern player’s cavity back shaped by feedback from the game’s most precise ball strikers. The series then expanded with the Mizuno Pro S-1, a pure muscle back created for players who prioritize ultimate control, workability, and direct feedback.
Mizuno Pro S-4 irons will be available September 17, 2026, starting at $215 a club.
