The Mizuno S-1 irons are new for 2025 with the pure muscle-back forged blade a successor to the Pro 241 model.
The new design replaces the Mizuno Pro 241 in the brand’s lineup and targets purists and tour players as one of the most stylish blades on the market.
Like the previous model, the S-1 irons provide ultimate precision feel and shot-shaping ability with some design tweaks extracting more improvement.
The S-1 is the latest release in Mizuno’s Signature Series and joins the already-launched S-3 irons, which is a shallow cavity-back iron with the classic look of traditional blades.
Mizuno Pro S-1 Irons Specs & Design
The S-1 irons are an upgrade of the Pro 241 but remain a stunning blade with a compact shape, square toe, thin topline and a tour-inspired straight edge for preferred visuals at address.
Once again, this model is a forged blade designed primarily for elite and better players who demand ultimate precision, feel and shot-shaping.
Like all Mizuno blades, they feature a Grain Flow Forged HD Construction with each iron forged in Hiroshima from a single billet of 1025E Pure Select Mild Carbon Steel.
The result of the forging process in Japan is a very tight grain structure for exceptional feel, feedback and consistency through the set.
The S-1 features a subtle channel running through the back to redistribute mass vertically and bring the center of gravity (CG) closer to the ideal strike point, improving launch consistency and stability.
There is also a thin layer of copper that sits beneath the chrome plating of the irons to subtly soften vibrations and delivering a signature “buttery-soft” feel Mizuno irons are renowned for.
The Harmonic Impact Technology (H.I.T.) helps fine-tune the club’s sound and vibration for enhanced feel through impact.
Mizuno have opted for Refined Sole Geometry in the S-1 with a flatter camber, a sharper leading edge and one additional degree of bounce compared to the previous 241.
The new sole design helps reduce digging and improve forgiveness on shallower strikes for maximum distance time after time.
In a switch from the Pro 241 series, Mizuno have removed the 3-iron option in the S-1 range with the set not contained only 4-iron (24 degrees) to Pitching Wedge (46 degrees)
Mizuno S-1 Irons Review: Are they any good?
The S-1 serves as a solid successor to the Pro 241 with feel, control and feedback what they are about rather than forgiveness and distance.
For those seeking more forgiveness, the S-3 is the go-to option in the Mizuno lineup as a compact players’ cavity-back…but it is feel you want the S-1s really are the business.
The tweaks made from the Pro 241 to the S-1 have enhanced performance of these blades, including the sole refinement helping to add consistency to ball striking.
They are one of the best classic muscle-back blades launched in 2025.
FAQs
What is the Mizuno S-1 irons release date?
The new irons were released in July 2025.
How much do Mizuno S-1 irons cost?
The irons retail at $215 per club or around $1,400 for a seven-club set.
What are the Mizuno S-1 specs?
There is no 3-iron in the S-1 range, a switch from the Pro 241 series. The S-1s are now available in 4-iron (24 degrees) to Pitching Wedge (46 degrees).
James is an avid golfer and reviews golf equipment and new gear for GolfReviewsGuide.com as well as providing the latest golf news. You will find him on a golf course wherever possible.
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