shop
Discontinued

Seikonaut Watch Case - 40mm

Your parts arrive as one finished watch. Our watchmaker seats your movement, aligns crown & stem, presses the caseback and QC-checks the build. 3–5 business day lead time, assembled in Singapore.

BUILD YOUR OWN WATCH.
ONLY 4 main components are needed to complete a watch.
Watch Case
Dial
Hands
Movement
Bridge & Rotor (optional)
Movement Holder (optional)
Tweezer (optional)

HOW TO START?

  • For a complete watch, select your (1) Dial, (2) Hands and (3) Movement.
  • To decorate movement, select your (4) Rotor (optional).
  • To have watch assembled, select (5) Assemble Watch. Please note that assembling the entire timepiece requires 2 to 5 business days prior to shipping.

Engineered by us and made exclusively for us with quality assurance by ISO 9001 Certified manufacturers.

FREE WORLDWIDE SHIPPING
From the iconic nautilus and Japanese Seiko comes the hybrid, Seikonaut.

Our own reinterpretation, every part, notches and crevices was redesigned from scratch. Creating a whole new allure and a refinement of the iconic design.

This Seikonaut case comes complete with clear AR sapphire, sapphire caseback, screw down crown and solid brush and polished bracelet. Additionally, it has a water resistant of 200m.

Designed to fit all of our dials (28.5mm) and original NH movements (grey dial holding spacer).

**Please note that assemble watch option will assemble the entire timepiece ready for use and requires 2-5 business days prior to shipping.

For black edition, visit here

Customers praised this 40mm watch case for "impeccable" quality and finishing. The integrated bracelet features screw-based links and solid construction. Reviewers noted "top notch" fit and finish, comfortable wear, and ease of assembly. Some mentioned crown sticking issues requiring stem adjustment. Fast shipping and excellent customer service highlighted.

  • The build quality and finishing are top notch and it wears SO well.
  • The bracelet integrates perfectly with the case. Couldn't be happier with this build!
  • The case quality and finishing is better than I expected.
Service (positive)Shipping (positive)Finishing (positive)Bracelet (positive)Case (positive)
  • 5 stars: 48 (94%)
  • 4 stars: 3 (6%)
  • 3 stars: 0 (0%)
  • 2 stars: 0 (0%)
  • 1 star: 0 (0%)
K
K S. (Edmonton, CA)
Naughty

A remodelled mod. Iteration 3 of this gorgeous case finally sticks! Adriel helped me out after I ruined the crown spring, and continues to be a stand up member of the modding community. Thanks again!

C
C. (Jackson, US)
Using this mod part for: Aftermarket Aqua Case, nh38
This case is awesome

This case and band are super high quality, I did a custom build with open heart birch dial and nh38 movement. I the first hands I used I didn't like so I switched them to a easier to read sportier hand. I uploaded pics of both.
Fast delivery. Very comfortable to wear. It is a very classy look. I will probably buy another of these cases and do a second mod.
I have purchased multiple movements here now and they are much better then the ones I had been buying at Crystal Times, every one from LA has been 6s or less. The CT regulated have been around 25s which is not acceptable. I just dial them in further on my time Grapher. I have been able to get the ones from LA dialed in to 1 or 2s.
Great service, everything I have ordered has been top notch.

C
Chris (Belmont, US)
Using this mod part for: LA Seikonaut
Wow…just wow

Having bought from LA before, I knew I’d be getting a quality product but this has far surpassed my expectations. The build quality and finishing are top notch and it wears SO well. This may just be my #1 watch of the summer!

H
Hubert T. (Warsaw, PL)
Using this mod part for: aftermarket
I like it!

I was suprised by the quality of polishing and details. What's more important the seikonaut by luciusatelier is not a PP ripoff or how you say "homage" but completely new design inspired by - which makes this watch interesting :)

G
Greg G. (Claremont, US)
Incredible quality and value!

The quality of the design, fit and finish are impeccable. The bracelet integrates perfectly with the case. Couldn't be happier with this build!

E
Eliud M. (Helsinki, FI)
Using this mod part for: Seikonaut
Amazing

It’s my second case I get from here and the quality is amazing, I got the hands and the dial also( one of the most beautiful that I’ve seen). The only thing I could say about it is that I think it should have come with half links in the bracelet for a better and nicer adjustment for all sizes of wrist. Other than that this is amazing.

S
Samir B. (Marseille, FR)
Using this mod part for: Seiko samourai
Absolutely stunning

Better than the the pictures

S
Sena P.
Using this mod part for: SARY147
High quality, comfortable to wear

Great case for my SARY147 mod. Integrated bracelet is very comfortable. The polishing and brushing are immaculate.

F
Flo (Neuilly-sur-Seine, FR)
Using this mod part for: Seikonaut case
My precious Seikonaut

First, this case is beautiful by itself and perfectly done. Very easy to build, every part is machined well and fit together without the need for any adjustments from me.
Now, let's talk about the service. I pre-ordered the case and misread the estimated delivery date (my fault), so when the case was ready to ship, I was out of my country for a long time. I just send an email asking to keep my order till I came back and very quickly got an answer from Adriel telling there was no problem. I just send a mail when I came back (more than a month later) and the package was send the same day !
To conclude I'll say that this was perfect from start to end ! Product quality, service and quick shipping !

J
Jorge F. (San Juan, PR)
Using this mod part for: 40mm Lucius Atelier Seikonaut case
High Quality Case

The look of this case is amazing. Fit and finish are superb too. Only reason I'm giving 4 stars is because the crown had to be worked a lot to fit perfectly. Out of the box the crown kept getting stuck in the compressed position. Stem length is crucial for proper fitment. Build shown is Lucius Atelier 40mm Seikonaut case, Namoki mods sakura navy dial, snowflake hands, and regulated NH35.

M
Muaxayan S.
Using this mod part for: Aftermarket seiko
Amazing stuff

I ordered this case for a mod and the goods perfect. The build quality is on par with swiss brands. I really liked the case and loved the way my watch turned out. I will buy more of these cases.

B
Brad (Sacramento, US)
Excellent quality!

Great design. The proportions work very well.

A
Alex S. (Greenwich, US)
Using this mod part for: Full build from scratch.
Top Tier

I would like to think that I have ordered just about every case quality there is. These cases are definitely as good as they come. From the type of stainless to the finishing, by far the best case I have ever ordered. I have read a few complaints where some would like to have their crown of choice for these cases which I could agree with in some ways but the crown used suits it perfectly fine. Will definitely be wearing this more than my others in the foreseeable future.

M
Muhd N. (Singapore, SG)
Seikonaut mod watch

Bought a seikonaut watch with a snowflake dial and was very satisfied with the outcome. Watch turns out great..really love it!!! And adriel was very nice in accommodating my request..the service was excellent..thanks adriel!! Definitely will purchase more from u guys.. cheers!!

A
Anonymous (Makati City, PH)
Seikonaut Mod

Absolutely amazing case. Fitted it with a NH36 movement and aftermarket dial. Very impressed with the outcome.

J
Jan F. (Oslo, NO)
Using this mod part for: Seiko 5 snkk87
Its a stunner!

Fast shipping, great service. The Seikonaut is awesome! Alot of bang for the buck!🔥 As you can see on the pictures, I brushed the middlelinks on the bracelet.

J
Jan W. (San Jose, US)
Using this mod part for: Seikonaut
My first Seiko Mod

Super fast shipping to California! And I really love the look of the Seikonaut!

Thank you again!

J
Jacob M. (San Francisco, US)
Using this mod part for: Seikonaut
Insanely Good Value

This case is almost perfect (would like to see a bit more taper to the bracelet) and for the price cannot be beat. I ordered this fully assembled -- it was shipped quickly, well packaged, and is ticking away nicely on my wrist.