Omega · Seamaster Diver 300M
Strap for Seamaster Diver 300M Master Co-Axial 42 Stainless Steel / Sedna Gold / Blue / Bracelet
Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.
Lug width
Recommended spring bar
Straps for the Seamaster Diver 300M 210.20.42.20.03.002 (aka: 21020422003002)
Selected for the 20 mm lug width · workshop selection
Black Alligator Strap with Light Blue Edges€149
Red Alligator Strap Water Resistant€195
Green Rubberized Alligator Strap with Ecru Tribal Stitching€149
Military Alligator Green Strap€138
Hammered Calfskin Strap Light Blue€98
The Seamaster Diver 300M 210.20.42.20.03.002 (aka: 21020422003002), seen from the bench
Frequently asked questions
What is the lug width of the Omega Seamaster Diver 300M 210.20.42.20.03.002?
The <a href="/pages/termine-glossario/misura-ansa">lug width</a> of the Seamaster Diver 300M in reference 210.20.42.20.03.002 is 20mm. This value is fixed for this 42mm case and is measured from the inside of one lug to the inside of the other. Any strap must have an exact width of 20mm to fit correctly without play or forcing.
What is the best strap material for the Omega Seamaster Diver 300M 210.20.42.20.03.002?
There is no single choice, but three categories meet different needs. <a href="/pages/termine-glossario/alligatore">Alligator</a> in <a href="/pages/termine-glossario/concia-vegetale">vegetable tanning</a> is the most sophisticated solution for occasional wear, with pronounced grain and natural patina; <a href="/pages/termine-glossario/shell-cordovan">shell cordovan</a> offers formal elegance and subtle aging; rubber or NATO straps maintain authentic diving heritage and resist moisture. The choice depends on the intended balance between formal and sporty use.
How do you change the strap on an Omega Seamaster Diver 300M?
The Seamaster Diver 300M uses straight lugs and integrated passants in the case. Remove the <a href="/pages/termine-glossario/deployante">deployant</a> or traditional buckle by pushing from beneath the lugs; then gently extract the strap from the passants. Insert the new strap (20mm width) by sliding it through the passants from above, then reinsert the <a href="/pages/termine-glossario/deployante">deployant</a>. The operation takes less than two minutes and requires no special tools.
Can I fit an aftermarket strap on this Omega?
Yes, any strap with a 20mm width is compatible with the 210.20.42.20.03.002. Compatible straps can be leather, rubber, fabric or metal: the important thing is that the width is exact to avoid play or damage to the lugs. MilanoStraps offers a complete collection of 20mm straps customizable in leather, color and stitching thread.
How long does a leather strap last on an Omega Seamaster Diver 300M?
Durability depends on the material and usage. An <a href="/pages/termine-glossario/alligatore">alligator</a> in <a href="/pages/termine-glossario/concia-vegetale">vegetable tanning</a> used occasionally can last 5-7 years; a <a href="/pages/termine-glossario/shell-cordovan">shell cordovan</a> can last 8-10 years due to its greater intrinsic resistance. Frequent exposure to salt water or chlorine shortens the lifespan, as does high humidity. Minimal maintenance (drying after bathing, annual conditioning) significantly extends the longevity of the leather strap.
The next step
The right strap isn't chosen. It is built, together.
From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.
Request an appointment →Casati Milano · Via XX Settembre 15, Milan · by appointment only