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Swiss Watchers

Seiko Seamaster 300 GMT Mod

Seiko Seamaster 300 GMT Mod

Regular price $400.00 USD
Regular price $460.00 USD Sale price $400.00 USD
Sale Sold out
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This is a unique and one-of-a-kind timepiece that combines classic Seiko craftsmanship with modern styling. This watch has been meticulously modified to feature a range of custom upgrades, including a new dial, hands, and bezel. The watch features a beautiful and unique dial design, with bold markers for optimal visibility. The watch is powered by a Seiko Calibre NH34 Automatic movement, which has been finely tuned for accuracy and reliability. The watch also comes with with a custom Seamaster 300 stainless steel bracelet. All of the watch parts that we use are sourced from the highest quality OEM aftermarket factories and original Seiko Parts ✅️

Whether you're a collector or simply appreciate the finer things in life, this custom-built Seiko Mod is sure to be a standout piece in your collection. Order yours today and experience the perfect blend of tradition and modernity.

This watch is based on a popular Diver GMT model.

In this mod we use a very high quality Mechanical Automatic NH34 Movement.


Seiko Seamaster GMT Mod Details


SEIKO NH34 automatic movement

Case diameter

41mm (without crown)

The thickness of the case


Strap width



  • GMT Function: The GMT function allows the wearer to track a second time zone, usually indicated by a 24-hour hand.
  • Date Display: GMT watch includes a date display, which can be useful when traveling between time zones.
  • Luminous Hands: The hands of the watch are luminous, making it easier to read the time in low-light conditions.


  • Date window at 3 o’clock position
  • Secondary hour (GMT) hand to track a second time zone

3ATM Water resistance


We Measure the accuracy and water resistance on all of our watch builds before shipping them out.



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  • Shipping Policy

    • All orders are processed within 1-3 business days. Once your order has been processed, you will receive a tracking number via email.
    • We offer tracking on all orders, so you can easily monitor the progress of your shipment.
    • Our products are hand-built by our watchmakers in Asia, so please allow for additional processing time.
    • We ship worldwide. Shipping time for UK, Germany, Italy, and France is 7-14 days. Shipping time for the rest of the world is 7-18 days.
    • Please note that shipping times may be affected by public holidays, customs inspections, and other unforeseen circumstances.
    • If you have any questions or concerns about your order, please contact us at

    Thank you for choosing Swiss Watchers for your Seiko watch mod needs. We strive to provide the best products and services to our customers and look forward to your continued business.

    We Offer Free Shipping On All Orders!