Seiko SKX Case Sizes 42.5mm vs 38mm

The Seiko SKX collection of watches has, since its inception around 1996, earned the wrists of millions of collectors around the world. The broad appreciation of the SKX largely stems from its agreeable design, sturdy construction, reliable movement, and affordable price.

However, not all have the wrist size to accommodate the base SKX case size which clocks in at 42.5mm. This case is the same seen on the standard SKX007 as well as the Pepsi SKX009 and the orange-themed SKX011.

Fortunately, there is an alternative: the SKX013. With a 38mm case, it poses a more manageable size while still boasting all the desirable aspects. That being said, there are some slight differences which I’ll be highlighting in the following article.

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Watch The Video Comparison

SKX 42.5mm

  • Diameter: 42.5mm
  • Lug-To-Lug: 46mm
  • Thickness: 13.4mm
  • Strap Size: 22mm
  • Water Resistance: 200m
  • Price: Discontinued
Seiko SKX007 Made in Japan Steel Watch On Black Rubber Strap Wristshot

SKX 38mm

  • Diameter: 38mm
  • Lug-To-Lug: 44mm
  • Thickness: 13mm
  • Strap Size: 20mm
  • Water Resistance: 200m
  • Price: Discontinued
Seiko SKX013K2 Wristshot

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The Standard SKX Case Dimensions

As alluded to in the intro above, the 42.5mm diameter SKX case is what can be considered the “standard” case size for this watch model. This is because most SKX watches have this case.

Along with the 42.5mm diameter, you can also expect the case thickness to be 13.4mm, the lug-to-lug distance to be 46mm, and the strap size (between the lugs) to be 22mm.

SKX009 vs SKX013 Case Size Dimensions Comparison

On the other hand, the SKX013, also known as the “Midsize SKX”, has dimensions that are slightly smaller but definitely noticeable when compared side-by-side with the SKX007 (or other standard SKX cases.)

Those dimensions are 38mm in diameter (“9 to 3 o’clock”), 44mm from lug to lug, 13mm in thickness or “tall”, and 20mm between the lugs.

Again, on paper, these differences seem minuscule. However, they make quite a significant difference for the individual wearing the watch as to those who are watching from afar. It’s also worth noting that both watches retain 200m water resistance so the size will not affect the diving specification of the watch.

Case Design

While they are very similar at a glance, the 42.5mm and 38mm SKX cases do have some slight deviations in their design. Namely, the case of the 38mm has lugs that are a bit sharper at their distal end. Additionally, the design of the crown guard is also sharper on the 38mm SKX.

The difference in the lugs is also noticeable from the top; you may note this in the previous picture while the below one serves to see the lugs from their sides.

Comparison of lugs on SKX 38mm and 42.5mm

Aside from the differences in the lugs, most other discrepancies between one case size and the other are simply proportional differences. This is to say, the design is the same except it’s been made smaller in the 38mm SKX.

As an example, note how the diver’s bezel on both watches is the same except for the fact that it is slightly smaller in the 38mm SKX (on the right in the previous picture.)

When it comes to the finish on the case, both watches have a brushed surface finish on the top and a high-polish finish on the case flanks. Both

Dial Details

Black Dial Divers Bezel Closeup SKX013With how noticeable the difference in case sizes is, it’s almost surprising that the dials on both these SKX case sizes aren’t more different. However, Seiko has done a proper job keeping the proportions of the dial elements, such as the hour indices and the date window, seemingly exactly the same.

If you’re more detail-oriented, you may notice that the hands in the 38mm SKX, particularly the minute hand, do in fact have a different design. However, this is yet another small detail that could be easy to overlook.

Movement Differences

If you thought that these two differently-sized watches may be powered by different movements, then you’d have been in the same camp as me before I did my research on these two Seiko SKXs.

Seiko SKX Automatic Caliber 7S26 MovementOften watch brands will employ different movements in different case sizes, even if they have the same complication, as it’s important for a caliber to fit properly into its case.

However, both the 38mm and the 42.5mm SKX watches are powered by the same movement – the Seiko 7S26 day-date movement. This automatic watch caliber boasts a 41-hour power reserve and -35/+45 seconds per day accuracy.

Overall, for the purposes of this comparison, the movements used in the two differently-sized SKX watches are exactly the same.

Strap And Bracelet Options

In a majority of cases, you’re likely to find the 38mm SKX013 sold on the stainless steel Seiko Jubilee bracelet that you see in the pictures.

Given that its strap size is the common 20mm, you could very easily purchase a couple of different fabric or leather straps and change the look of the watch. Yet, I’ve found that the 38mm SKX looks great on the standard bracelet.

The 42.5mm SKX models are likewise sold on a very similar Jubilee bracelet, however, they are also commonly found with the rubber Seiko “Wave” strap. The 22mm strap size of the 42.5mm case size is also a universal strap size for which you’ll find many strap options.

Final Thoughts

Now that I’ve covered the most obvious differences between the 42.5mm and the 38mm SKX watches, I can finally get to my favorite part – giving my opinion!

Seiko SKX013K2 Diver Midsize On Jubilee Bracelet

After having spent some time with both models, I found myself reaching for the SKX013 more often simply because I believe the smaller size fits and looks better on my wrist. I also enjoy the sharper case design a bit more than the traditional 42.5mm SKX.

Yet, many collectors prize the SKX exactly because it looks bulky on the wrist. This isn’t intended to be a dressy watch that you can hide under a wrist cuff; it’s a tool for professional divers to take with them to the depths. I can definitely understand this aspect but I personally choose comfort over ‘authenticity’ when it comes to my timepieces, at least for the time being.

What are your thoughts? Have you tried either or both of these SKX models and if so, do you have a preference? Let me know in the comments below! Otherwise, feel free to check out some of our other related watch pages:

Shop SKX007 On eBay
Shop SKX013 On eBay

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