Royal Oak Seiko Mod
Royal Oak-style Seiko mods from Nomods — available as prebuilt watches or individual parts for custom builds. Choose between the ultra-thin 37 mm case (9.95 mm thick, integrated bracelet) and the larger 41 mm case (12.2 mm, rubber strap). Both sizes run NH35 automatic or NH72 skeleton movements, with sapphire crystals and 100 m water resistance across the range. The collection includes complete watches in skeleton and waffle dial configurations, plus standalone cases, 28.5 mm and 30.8 mm dials, V1 and V2 hands, straps, and accessories.
Fits: NH35, NH36 (solid dial) · NH72, NH70, NH71 (skeleton) · Case sizes: 37 mm (V2) and 41 mm · Dial sizes: 28.5 mm (41 mm case) and 30.8 mm (37 mm V2 case) · Watch out: The 37 mm V2 case uses 30.8 mm dials, not the more common 28.5 mm size. The 41 mm case uses standard 28.5 mm dials. Check your dial size before ordering — read our dial size guide for a full breakdown.
How to Choose Your Royal Oak Seiko Mod
The Royal Oak collection covers a wide range of builds. Here is how to narrow it down:
37 mm vs 41 mm: The 37 mm is the thinner, dressier option at 9.95 mm with an integrated steel bracelet — it wears closer to a luxury daily watch. The 41 mm is a bolder, sportier build at 12.2 mm on a rubber strap, with more wrist presence. If you want something that disappears under a shirt cuff, go 37 mm. If you want something that stands out, go 41 mm.
Skeleton vs solid dial: Skeleton builds (NH72 movement) show the movement through the dial and caseback — they are visually striking but harder to read at a glance. Solid dial builds (NH35 movement) with waffle or textured dials offer cleaner legibility and a more traditional look.
Movement: The NH35 is the reliable workhorse — automatic with hacking and hand-winding, 41-hour power reserve. The NH72 is the skeleton variant with the same internals but an open-worked design. Both are Seiko Instruments movements. Read our NH72 movement guide if you are considering a skeleton build.
Case finish: Silver, gold, gunmetal, rose gold, and two-tone options are available depending on the case size. PVD-coated finishes (gold, gunmetal, rose gold) add visual warmth but may show wear over time on high-contact edges.
Beginner recommendation: Start with a prebuilt watch rather than individual parts. The 37 mm skeleton watches are the most popular in this collection and ship fully assembled. If you want to learn the modding process, our step-by-step build guide walks you through a complete build from case to finished watch.
Frequently Asked Questions
What movements fit Royal Oak-style cases?
Both the 37 mm V2 and 41 mm Royal Oak cases accept NH35, NH36, NH72, NH70, and NH71 movements. The NH35 is used for solid-dial builds and the NH72 for skeleton builds. All are manufactured by Seiko Instruments (TMI) and share the same mounting dimensions. Our NH72 guide covers the differences between skeleton and solid movements.
How do I choose between the 37 mm and 41 mm?
The 37 mm is thinner (9.95 mm vs 12.2 mm), lighter, and comes on an integrated steel bracelet — it wears comfortably at 37 mm and dressier occasions. The 41 mm has more wrist presence, comes on a rubber strap, and suits casual or sporty wear. The 37 mm also uses 30.8 mm dials while the 41 mm uses the more common 28.5 mm size, which matters if you plan to swap dials later. Read our dial size comparison for the full breakdown.
Is the Royal Oak a good first Seiko mod build?
Yes, especially if you start with a prebuilt watch and swap individual components from there. The Royal Oak cases are well-machined and the integrated bracelet on the 37 mm eliminates the need for strap fitting. If you want to build from scratch, our build guide covers every step from case preparation to final assembly.
What else do I need to complete a Royal Oak build?
A complete build requires a case, movement, dial, hands, and a crystal (pre-installed on Nomods cases). You will also need basic modding tools: a case holder, hand press, movement holder, and dust blower. If you buy a Nomods case, the sapphire crystal and gaskets are already fitted. Choose your dial size based on your case — 30.8 mm for the 37 mm V2 case, 28.5 mm for the 41 mm case.
Explore More Styles
- Nautilus Seiko Mod — integrated bracelet, 40 mm, skeleton and solid dial builds
- Aquanaut Seiko Mod — grid-textured dial, rubber strap, sporty-luxury design
- Petrichor 37mm — original Nomods design, domed sapphire, integrated bracelet
- Royal Oak Parts — cases, dials, hands, and accessories for custom builds
Nomods is an independent brand. Our products are original designs inspired by iconic watch aesthetics. We are not affiliated with or endorsed by any luxury watch manufacturer. All brand names are used for reference purposes only.
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