SANTOS WATCH MOD COLLECTION

Seiko Santos Mods — square-case builds.

Your watch comes with a 12-month ModTime warranty.

Square-case style, chosen by dial and finish

The square-case outline gives Seiko Santos Mods a different starting point from round calendar watches. The face and case shape set the direction first; the dial color and finish let you make that direction your own. Choose a light dial for the white-and-silver theme, a colored face for a stronger accent, or a skeleton-dial version when the visible-mechanics look is part of the attraction.

The design reference is the Cartier Santos and the square dress-sport watch tradition. ModTime hand-assembles these independent custom builds, with the current product specifications and available options shown on each product page. ModTime is not affiliated with Cartier or Seiko.

Start with the finish you want around the dial. Silver White keeps a white face within a cooler silver-tone look. Two-Tone White brings a mixed finish to a white dial, while Gold White moves the surrounding color into a gold-tone direction. The silver-tone family also includes black, blue, brown, green and Tiffany-dial versions, so you can compare color without changing the square-case theme.

Compare the skeleton versions separately. Silver Skeleton and Black Skeleton bring the skeleton-dial look into different finish directions. Use their product photographs alongside the other dial versions to decide whether the visible-mechanics theme or the dial color matters more to your choice.

The current builds list NH38 automatic movements, 38 mm cases and sapphire crystals. Once you have chosen the look, select LOGO or NO LOGO and the listed standard 3 ATM or paid 5 ATM option on the product page. Review the selected configuration and displayed price before adding your watch to the cart.

How to choose your Santos build

Compare Silver White with Two-Tone White, choose the color of Silver Tiffany, or explore Silver Skeleton.

Compare Datejust-inspired calendar watches or read the movement guide.

Questions before you choose

Who makes these Santos-inspired watches?

ModTime hand-assembles these independent custom builds. The design reference is the Cartier Santos; ModTime is not affiliated with Cartier or Seiko.

Which movement do the current builds use?

The current products in this collection list NH38 automatic movements. Check the selected product page for its exact configuration.

What case size and crystal are listed?

The current builds list 38 mm cases and sapphire crystals. Compare the case proportions with a watch you already wear.

How do I choose the configuration?

Open the product you want, select LOGO or NO LOGO, and select standard 3 ATM or the paid 5 ATM option. Review the selected configuration and displayed price before adding it to the cart.

How do I choose between the looks?

Compare Silver White and Two-Tone White for white-dial versions in different finishes. Compare Tiffany, blue, brown and green for a colored face, or Silver Skeleton and Black Skeleton for the skeleton-dial look.

How long does assembly and delivery take?

Assembly takes 4–6 working days, followed by 7–12 days in transport.

What warranty is included?

Your watch comes with a 12-month ModTime warranty.

Need Help?

Frequently Asked Questions

What is a custom ModTime watch?

A ModTime custom watch is an independently assembled watch built from compatible components around a chosen movement, case, dial and bracelet.

The term "MOD" comes from "modification". These modifications are generally made for those who wish to personalize their watch according to their specific tastes or needs. Modifications can vary considerably, from minor aesthetic changes to more complex technical revisions.

What makes Seiko watches particularly amenable to modification is the wide availability of spare parts. This abundance of components enables a wide range of customization, making each ModTime custom watch unique.

Which movements do we use?

At ModTime, we work exclusively with reliable, high-grade Seiko movements — trusted by watch enthusiasts worldwide for their precision and durability.

Each movement is carefully selected and tested by our watchmaker to ensure optimal performance and a smooth mechanical experience.

We use:

  • NH34 Automatic — for our GMT Mods
  • NH35 Automatic — for date dial builds
  • NH38 Automatic — for clean dial designs without a date
  • VK63 Mecha-Quartz — for chronograph models


Every ModTime watch is powered by a movement chosen for its accuracy, longevity, and craftsmanship — the foundation of every timepiece we create.

Can I adjust the watch size myself?

Absolutely! Every ModTime timepiece comes with a FREE complimentary premium adjustment kit, allowing you to resize your bracelet easily and safely at home.

Each tool is designed for precision and comfort — the same way our watches are crafted.

If you prefer, your local watchmaker can also assist you with the adjustment — our bracelets use standard Seiko-compatible links, making professional resizing simple and effortless.

Can I choose a clean or dial-marked version?

Yes — absolutely! Every ModTime timepiece can be fully customized to match your personal vision.

If you prefer a clean, minimalist dial without visible dial branding, our watchmakers will assemble your piece accordingly during the hand-crafting process.

Simply include your preference in the order notes at checkout, and we’ll ensure your watch is built exactly the way you want it — refined, personal, and uniquely yours.

Can I design my own watch?

Absolutely. At ModTime, every timepiece can be crafted to your personal vision — from the bracelet and case to the dial, hands, and finishing details.

You can even add your own logo or initials, turning your watch into a truly one-of-a-kind creation.

If you’d like to design a fully personalized ModTime piece, simply reach out to us on WhatsApp. Our watchmakers will guide you through every step of the customization process — from concept to final assembly.

Shipping Time and Costs

Free tracked shipping to the US. Import costs are included; there are no import surcharges on delivery. See checkout for the final order total.

Each watch is hand-assembled within 4-6 days to ensure the highest quality and attention to detail.

Once completed, the shipping time is 7-12 days, depending on your location. While we aim for prompt delivery, some variations may occur based on the destination.

Please note: Due to the current global shipping conditions, especially related to parcel traffic in and out of the US, delivery times may occasionally be slightly extended. However, we do everything on our side to ensure the fastest possible handling and dispatch.

Please note that delivery times may vary depending on the destination country.

Are the watches water resistant?

ModTime watches use variant-dependent water-resistance options such as 3 ATM or 5 ATM. 3 ATM is intended for daily splashes and rain. 5 ATM gives more everyday margin, but custom watches should still be kept away from swimming, bathing, diving and prolonged water exposure unless a specific model is explicitly rated for that use.

No answer matches that yet. Try a broader word — or reach our watchmakers on WhatsApp and we’ll help directly.

Explore related collections: GMT watches · integrated bracelet watches · open heart watches · chronograph watches · watch travel cases · all watches

Questions before ordering? Read the ModTime FAQ or contact ModTime.