What Is A Seiko Mod? – And Why It Is Not A Fake Rolex

The term Seiko Mod stands for Seiko modification.

With a base of a Seiko movement, everything around it is customizable.

The choice of which dial, hands, case, glass, bezel and strap are used is entirely up to you.

Seiko modding is perfect for watch modders because of the plenty of aftermarket and spare components accessible on the open market.

Read on to find out everything you need to know about modified Seiko watches.

Two Modified Seiko “Homages”

Where Does The Idea Of Modifying Seiko’s Come From?

This idea of taking a movement from Seiko and putting the rest of the watch together with your own parts originated in Asia.

People wanted something original on their wrist but with the confidence that it won’t break like most “cheap” watches would do.

Seiko making movements for their own watches and movements to distribute to other watchmakers made the perfect base for these modified watches.

From the base, people went all crazy with their creations.

Making watches to their own taste and pieces that looked like something else.

Most people could not afford the expensive Rolex or Patek watches, so they started to make their own.

This was fine, while the timepiece didn’t show any branding from another company.

The Parts Used For A Seiko Mod

The Seiko Mod its base is a Seiko NH35A movement.

This is the brandless powerhouse of the Seiko Caliber 4R35.

Seiko makes the NH35A, especially for non-Seiko watches.

The NH35A is an automatic movement with a power reserve of 41 hours.

For all the specifications of the NH35A, click here.

The NH35A Movement

Other parts that are used for a modified Seiko are all brandless.

This means no brands or logos are shown on the watch except for the Seiko movement logo.

Cause of the use of these brandless parts, the watch looks very clean and feels premium.

The parts are made out of 316 RVS steel. Watches can use a sapphire crystal or plexiglass.

Nevertheless, they are both water-resistant up to 50m.

These parts are used for the “homage” watches; if you go with your own design, you can pick any dial, hands, case, glass, bezel, and strap your heart desires.

The time it takes to create a Seiko mod is around 6-hours.

Although this can differ, the more personalized your watch gets.

Is A Seiko Mod Not A Fake Rolex?

A Seiko Mod is not a fake Rolex watch. Seiko mods do not wear the Rolex branding.

Although having the looks of some Rolex models, they are a “homage” to them, showing honour to the big watch brand.

While fake Rolex watches are being sold everywhere and should not be worn by anyone.

These Seiko mods give you the luxury feel you get from Rolex for a fraction of the price.

You can get a unique looking Seiko with a date function for just €250.

Where Rolex replicas are illegal to buy and sell, Seiko mods are not.

The modified Seiko’s are legal for you to purchase and for anyone else to sell.

So you don’t need to worry about taking your watch through customs.

Seiko Homage To The Rolex Submariner “Comex”

Where To Get Your Seiko Mod?

There is no official distributor for modified Seiko’s.

But more and more people are making Seiko mods and are offering these watches through social media or their own website.

I sat down with a Dutch maker called RCM Watches for this post.

RCM Watches holds a stock of their most popular Seiko mods, but you can also get your own desired watch.

Nothing is too crazy for RCM.

The maker works with a jeweller and another watchmaker to give the best quality possible.

The price for a pre-made Seiko mod is €250.

You’re getting an outstanding quality timepiece with a travel pouch and digital manual.

A Seiko From RCM Watches

For more info, check the Instagram page of RCM Watches @rcmwatches.

Another way to get your hands on a Seiko mod is to make it yourself.

You need to be very sure about your own technical experience because making a watch is nothing like building a lego set.


The guy who loves to chat about watches.

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