Seiko SBDC033 Review – My 3 Years Experience With The Blue Sumo

Seiko SBDC033 Review (Sumo)


Today I’m going to write about Seiko SBDC033 review, or better known as the Blue Sumo (or “Blumo” lol!). This watch is part of Seiko’s Prospex line up.

What makes this watch special is it’s one of my favorite watches that I’ve had for the past 3 years. I’ve been guilty of giving it lots of wrist time for the simple fact that it’s such a beautiful watch – even though it’s supposed to be a diver’s watch!


But before we get into my experience with it, perhaps some of you wonder why the Sumo nickname?


It seems the nickname came from the appearance of the watch which is a bit fat and big (it’s a 44 mm diameter watch) likening it to a sumo wrestler. But truthfully, I don’t think it’s that big.

Thanks to the curved lug case design, the watch hugs our wrists making sure it’s still wearable even for those with smaller wrists.


Seiko SBDC033 front


Putting that aside, the Sumo is a great diver’s watch with beautiful design, high quality case, superb movement and astonishing LumiBrite for very bright lume.

In terms of hierarchy, the Sumo can be regarded as a step up to the SRP series of diver’s (such as the Monster and SRP777 Turtle with 4R36 movement) due to its higher grade 6R15 movement.

And what makes the watch more special is the fact that I personally own the previous version of this Blumo (the Seiko SBDC003) for 3 years now and I absolutely love it (an owner’s bias? lol!).


Seiko SBDC003 vs SBDC033

So what is the difference between SBDC003 vs SBDC033? Well, in truth, not so much. The first Sumo is the SBDC003 (the one that I bought way back in 2014).

But sometime around 2015, Seiko wanted to promote their Prospex lines (Professional Specification, more on that later) and included this watch and many other automatic divers inside it.

This called for a slight change to the dial to include the Prospex “X” logo on it, which is what the SBDC033 has currently.

Apart from the minor dial change, the SBDC033 also purporterdly has an updated LumiBrite which supposedly gives the watch a better lume.

The older version Seiko SBDC003 (top) that I had and the newer version SBDC033 (bottom). Not really much change except on the dial’s signatures


And that’s it. The other aspects: case, design, bracelet are the same. As for me, I like the older one (SBDC003) better as the dial is less busy as compared to the newer SBDC033. Though you can say that I’m a bit biased because that’s the version that I have LOL!

While I totally love this watch, it also does has its own flaws which I’m also going to share with you guys in this review.

Without further ado, let’s check out the Seiko Sumo review.


Seiko Sumo Specification (SBDC003 and SBDC033)

Diameter: 44 mm
Thickness: 13 mm
Lug Width: 20 mm
Lug To Lug Distance: 53 mm
Case: Stainless steel
Strap: Oyster stainless steel bracelet

Dial: Dark blue dial
Watch Crystal: Hardlex crystal
Hands: Sword hands with lume
Markers: Circle index markers with lume

Movement: Seiko Caliber 6R15 Automatic self-wind movement
Movement Features: Seiko In-house movement, 23 Jewels, 21600 vibrations per hour or 6 beats per second, Hacking, Manual winding
Accuracy: +-25 seconds per day
Power Reserve: 50 hours

Water Resistance: 200 m
Other Features: Unidirectional rotating bezel, Screw down caseback and crown, Anti-magnetic case, Seiko’s LumiBrite lume, Date display, ISO 6425 Diver’s Watch Compliant

Best Place To Buy: Amazon (for the best prices), MSRP is $600 (according to Seiko USA website)



Seiko’s Prospex Line Up?

What is this Prospex line? It’s actually Seiko’s own “Professional Specification” watches designed for the most extreme conditions, be it sea, land or air.

All the watches in the line up are designed with full functionality for the convenience of the user. Notwithstanding that, the watches are also beautiful to look and wear, such as the case with this Seiko SBDC033.

Seiko Prospex

Seiko’s Prospex logo to signify a watch designed for professional use – this “X” is featured in all of their newest watches, including the Sumo


Beautiful Dark Blue Dial

On top of the SBDC033 is a matte dark blue dial which is so enchanting to look at. The Sumo also comes in black (SBDC031).

In my opinion, the blue dial is more unique and beautiful than the black color – which is also why I went with the blue sumo before.


Seiko SBDC033 Sumo side

Just look at that deep blue dial on the Seiko SBDC033.. So simple yet gorgeous and beautiful!


As with any other diver’s watches, the dial is simple to help diver’s tell time underwater. The index markers are big circle with triangle marker at 12 o’clock. The use of big markers definitely help to make the watch legible.

The sword hands are also big and bulky – for the exact same reason as the markers. All of these have surfaces fully applied with Seiko’s LumiBrite luminous material on top of them for bright glowing green lume.

Seiko’s lume is very famous for its brightness and long lasting lume. In fact, I don’t have any problem to make it last for at least one movie screening – provided you give them sufficient time to absorb light beforehand.


Seiko SBDC033 Lume shot

Great lume – very bright and legible. What I love about it is how easily it start to glow even in a somewhat dim room/condition =)


On the dial also is a date display window which is make it a very functional watch for work. I found the lack of day display sorely missing from the watch, but then not having the day display do make the watch more elegant.

The signatures are not too obstructive, though the new version of sumo (this SBDC033) has the Seiko Prospex “X” logo on top which seems to make the watch busier.

All in all, the dial of this blue sumo watch is very beautiful, thanks to the simple layout and gorgeous deep blue dial. I’ve used this watch for 3 years and has never fallen out of love of it =)


A Very Useful Unidirectional Rotating Bezel

Another characteristic of a diver’s watch is the unidirectional rotating bezel.


What does that mean?


That means the bezel can rotate only one direction which is anti-clockwise. It’s originally designed as a way for divers to keep track of time underwater which is why the bezel has minute markings on it.

Well, I’m not a diver but I’ve used the bezel for many other purposes – timing my workout and swimming time, waiting time for cook/baking, elapsed time in traffic congestion and many more!

Truthfully, any watch with a rotating bezel can do the trick, but I just want to let you guys know there are lots of possibilities of usage with the bezel on this sumo.


Seiko SBDC003 Sumo Dial

The Sumo with a matching blue rotating bezel that has many usages.


In terms of construction, the bezel is designed with 120-clicks which gives a very satisfying bezel action. You can hear the clicking noise as you turn the bezel, and its very loud and crisp.

I can’t count how many times I’ve rotated the bezel just for the sake moving it and hearing it clicks. And trust me, its so addicting too =)


Exquisite Case Construction

One of the things that Seiko is very good at is in case design and construction. Like the SARB033, the SBDC033 also has the distinctive and gorgeous case design with contours and curves all around it.

There are 5 surfaces on the lugs from top to bottom and each of them has very sharp transitions with impeccable layering of polished and brushed finishes – which is just surreal!


Seiko SBDC003 Sumo case side right

Seiko SBDC003 Sumo case side left

Just like other Seikos in the SARB line (SARB035 and SARB033), the Sumo also has that curved case that make wearing it soo comfortable


Seiko SBDC003 Sumo caseback

Above: the tsunami logo on its caseback


Seiko SBDC003 Sumo crown

Above: The Sumo also has a signed crown!


The effort put down into machining the case is really shown here. Apart from the gorgeous dial, the case is one of the things that I always found myself to look at, for no apparent reason lol!



Curved Lug Design To Fit Many Wrists

In terms of sizing, this Seiko SBDC033 is 44 mm in diameter, 13 mm thick and 53 mm lug to lug distance. Yup, it’s not a small watch for sure.


Seiko Sumo Lug Curve

Notice how the lugs curving down? It’s one of the best things about the case which hug the wearer’s wrist comfortably


You can see from the pictures that due to the elaborate lug design, the lug is quite long which contributes to the long lug to lug distance.


But will it fit a small wrist?


Unless your wrist is very very small, then my answer is yes. This is due to the lug which is curving down to hug the wrist.

I also has a tiny wrist with a wrist diameter about 2 inch, which is just about the same width as the lug to lug distance.


Seiko Sumo on hand

My wrist is not big at all (same diameter as the watch) but the watch sits on top of it easily. It might look over sized, but since the actual dial is small (the bezel is quite wide), it still looks great, at least to me =)


With any normal watch, it’s totally not possible for me to wear it but having the curved lug make the watch able to fit on my wrist easily. And it’s very comfortable too!

More pictures to show you guys how this Seiko Sumo fits onto my wrist perfectly


Oyster Bracelet With Diver’s Extension

As a traditional diver’s watch, the SBDC033 Sumo comes with an oyster bracelet. There is nothing fancy about the bracelet to be honest. It’s a normal bracelet with solid end links.


Seiko sumo side hand

The oyster bracelet that this diver’s watch comes with


I used to wear my Sumo with a rubber strap but in recent times I’ve changed it back to the original bracelet. I think it depends on your mood and preference at that time.

Being a diver’s watch, the bracelet comes with two extra things: double lock clasp and diver’s extension.

I really like the double lock clasp as it gives an extra protection to the watch from accidentally unlocking it. While I never use the extension before, I found it a cool feature to have lol!

Seiko SBDC003 Sumo dive extension 1

Seiko SBDC003 Sumo dive extension 2

The bracelet has double lock clasp and diver’s extension to be used with wetsuit (which frankly I never use lol!). To use it, simply push up the extension to disengage it from the bracelet (pictures above)



Trustworthy 6R15 Automatic Movement

Inside the Seiko SBDC033 is the workhorse 6R15 automatic movement. It’s definitely the Japanese brand’s answer to ETA 2824-4 in terms of movement quality.

The movement has 23 jewels, and has 6 beats per second. The lower beat count as compared to Swiss ETA with a typical 8 beats per second, make the sweeping second hand less smooth.

But on the other hand, the lower beat movement has the advantage of lower stress cycles in it and thus require longer maintenance interval.

It’s a modern movement with the standard hacking and manual winding features. I can’t stress how convenient manual winding has been for me to keep my watch running even when I’m not using it.

Accuracy wise, the movement has a published rate gain/lose of 25 seconds per day. But throughout my use, I found the watch to have a higher degree of accuracy, sometimes up to +-4 seconds per day with the dial face up to be the most accurate position.

Bear in mind that COSC chronometer has a maximum of +-6 seconds per day, so I’m thoroughly happy with how my 6R15 is performing. And the good 50 hours power reserve is very useful as I like to lay down my watch for the weekend =)


Watch this video to look at the Sumo up close


So What Happens With My Old Sumo or SBDC003 After 3 Years?

I’ve been very happy with my Sumo for the past 3 years. I’ve used it for everything: work, exercise, travel, parties and many more. The great thing about diver’s watches is how versatile it is.

Not to mention I have no worries about using it for exercise since it’s already designed for excessive hand movements of divers while swimming. So an hour of workouts would not do it any harm.

But, not everything is perfect. The Sumo is still a $500 watch (the price I paid 3 years ago) and it does come with its sets of flaws.

For instance, the watch crystal uses Seiko’s Hardlex crystal, which is an improved version of mineral crystal. It’s tough and resistant to impact, but I found it is not scratch resistant.

Scratches, big and small are present on top of my crystal. I’m not sure if it’s because I’d bang them into concrete walls clumsily many times before, but for Seiko to not put a sapphire on a watch at this price is very hard to understand.


my Seiko Sumo SBDC003 hardlex

Hardlex crystal is still a mineral crystal, and it’s not as good as sapphire to protect our watches from scratches. Notice also the chippings on my Sumo’s bezel insert…


I mean, even the lower priced SARBs (SARB033 and SARB035) have sapphire crystal on them so it totally does not make sense for them not to put it on a more expensive watch.

Next, I found the aluminum insert on the bezel is not durable as what I’d expect. The bezel insert is easily damaged if you hit it with a hard material.

But to be fair to Seiko, this problem also affects other brands as well. Perhaps the latest ceramic bezel by Rolex is the best solution to this old-age problem.

Lastly, the stainless steel case and bracelet are also not scratch resistant and would pick up grazes once in a while. Again, it’s not Seiko’s fault as this is a universal problem with all stainless steel watches.

The reason why I shared this flaws are to make sure you guys are fully aware of the shortcomings that a watch will have so that you will know what’s in store with them.


How About Seiko 6R15 Movement Accuracy?

Moving on to the automatic movement inside my Sumo, the Caliber 6R15, especially on the question of accuracy.

When I first got it, it kept superb time. It consistently making less than 5 seconds deviation per day, which is truly outstanding especially for a non-Swiss movement. Not to mention that’s on par with chronometer specifications =P

In terms of power reserve, the 6R15 got through 50 hours just fine, though this is not something that I ever measured. All I know is the watch is still ticking come Monday morning, just in time for me to go to work.

But fast forward 3 years later, I found the accuracy had dropped off which can be attributed to various factors such as magnetized, adjustments etc.

To be precise, I’ve used the WatchCheck app (on Google Playstore) to easily measure its accuracy. I measured it for 2 cases:

1- Normal weekday use of the Sumo

2- Normal weekday use of the Sumo but with daily manual winding

Below are the results:

Seiko Sumo 6R15 accuracy test (1)


Seiko Sumo 6R15 accuracy test (2)

The first picture shows that the average rate of the Sumo/6R15 is +34 sec / day for the normal use case.

On the other hand, the second picture for the daily winding case shows the average rate is +21.5 sec / day.

The reason for this 2 cases is I want to show that manual winding really helped in terms of an automatic watch accuracy – which was right judging by the result.

By the way, there’s no reason to fear that daily winding will break the Sumo as Seiko had stated on its instruction manual that daily winding of the 6R15 is fine. Below is the excerpt from the manual:


6R15 manual winding everyday


Obviously, I’m not happy with such accuracy results but it’s totally within my expectations. Nothing can last forever, and that’s really true for mechanical watches where its accuracy depends on it being in the perfect condition.

The only way to ensure its accuracy to be perfect after all these years is by keeping it pristine inside my watch box. But that’s totally unacceptable for me =)

Why would I not use a watch that costs hundreds of dollars? The joy of owning a watch is using it and these are the results of using the watch for its intended purposes.


So what will I do with the Sumo?


A visit to my watchmaker is in due course. Since it’s still less than 5 years old, I don’t think I need a full service to be done on it. I believe an adjustment would do just fine to restore the 6R15’s accuracy back to its former glory.

Again, I need to emphasize that I’ve used this watch for many physical activities (swimming, jogging, gym sessions, etc.) which I believe contributed to its current state of accuracy.

Bear in mind that out of the box, the Sumo’s accuracy is unbelievably good and I’ve been a very happy owner for years.


What Is My Verdict Of The Sumo?

Even though it does not have a sapphire crystal and it’s accuracy had worsen over the years, it’s definitely a very good value for money. It’s super sleek and gorgeous.

Plus, the robustness of a Seiko diver’s watch make me feel comfortable using it for almost any activities.

I’ve done exercises, went to gym, ran and of course, swam with it. I never had the opportunity of testing the 200 m water resistance (because the thought of diving scares the hell out of me LOL!) but suffice to say, the water resistance is good enough for normal people with some water activities here and there.

To me, the Seiko Sumo is a very dependable automatic watch for everyday use.

My only regret is that I did not take better care of it. If only I’d be more careful while using it, I might be able to preserve its beauty and avoid those ugly scratches…..


Who Is This Watch For?

So who is this Seiko Sumo for? I believe divers would do well with this. Just like other Seiko divers, the SBDC033 also is ISO 6425 diver’s watch compliant and will definitely be a great tool.

But if you are not a diver, then this watch is an excellent watch because of its versatility which enables you to wear it for any functions and events, except for black tie events of course.

The Sumo is definitely a good value for money diver’s watch.  And lastly, if you like blue color, you’ll definitely love this watch!

While the Sumo’s MSRP is around $600, the watch can be had for lesser than that on Amazon (depending on shopping seasons and availability, of course). Check out Amazon on the current price of the Sumo (click the link below to know more).


=>Get Seiko Sumo SBDC033 Here


Who Should Not Get It?

Those who want a true dress watch should not get the Sumo as it’s a bit sporty and won’t look as dressy.

You might want to check out the other dress watches such as Tissot Visodate, Orient Star Retrograde or Seiko SARB033 and Seiko SARB065 Cocktail Time for more dressy watches.


Seiko SBDC033 Sumo Pros and Cons


  • Beautiful design with gorgeous dark blue dial
  • Solid and exquisite craftsmanship
  • Bright and long lasting lume
  • Curved lugs to comfortably hug wrist
  • Great bezel design and action


  • Hardlex crystal is not scratch resistant
  • Solid stainless steel in a 44 mm watch can be a bit heavy for some people not used to the extra weight



Final Thoughts

Seiko Sumo is a famous watch among Seiko fans due to its more traditional look, as compared to the other Seiko divers such as Seiko Monster and Turtle watches.

And even with a traditional style, Seiko managed to make it look gorgeous, and coupled with great craftsmanship plus affordable prices, they have a really good value for money automatic watch here.

I’ve used the older version of this blue Sumo for 3 years and while I find the non-scratch resistant Hardlex crystal to be very annoying, I still love how beautiful the dial and case is. It’s definitely a watch I’m going to keep for a long time.



Hope you guys find this Seiko SBDC033 review to be helpful. Let me know if you have any other questions about this watch.

Drop your questions below and don’t forget to subscribe to this site =)

Till next time. Cheers!



  1. Although I may not be a huge watch fan, I do appreciate quality craftsmanship when it comes to watches. I currently own a Tag Heuer Carrrera 100 meter that seems to do the trick for me. I have heard it said that many many successful CEOs can be found wearing a Seiko watch and so I can appreciate such a timepiece. Your review obviously comes from a lot of experience in the watch business. The pitcher is very clear and detailed oriented. I am sure that the watch that you have featured here probably cost a lot less than the watch I currently own. Can you tell me the differences (other than the Swiss movement and Saphire crystal dial, etc.) that makes the watch that I own so much more expensive?

    1. Author

      Hi there. I think the main aspect of why Swiss/German/American (basically watches made from western countries) have the disadvantage of higher costs.

      This cost comes from:

      1- Higher manufacturing cost – labor, material, etc. I mean it’s far cheaper to make something in Asia right?

      2- Marketing cost – Swiss watches have lots of ads, both printed and online as compared to Japan watchmakers. You rarely any Seiko ads save for their highest end watches in magazines

      3- Retail cost – watch boutiques can cost a hefty sum to set up. This will add up to the margin of profit which increase the price of the watches.

      These 3 are the main reasons why Japanese watches (Seiko, Orient, Citizen) can produce cheaper watches than their western counterpart.

      Not to mention the watches on Amazon are taken directly from the dealers, so the retail cost is significantly cut which further reduce its price.

      What do you think about this buddy? Am I making a valid point here? =)

  2. Amazing and very well written review you have here. I enjoyed reading it and decided to make a buying decision all because it. I haven’t purchased anything through Amazon before. But now I will and see what the experience is like. Thank you for the information and I will share this article.

    1. Author

      Hi James. I’m glad that you enjoy this review and decided to buy the Seiko Sumo. I’m sure the watch will serve you well, just like how it has served me all these years =)


  3. These review is outstanding. I’m not very educated on the quality of watches, but I have definitely been looking into picking up a nice one. After reading this, there is A LOT more that goes into a nice watch than I thought.

    If possible, could you point me towards a “sports” watch that also tells the date and time? And perhaps one with more precise fitting… in the past I had one where one hole made the watch too loose and the other too tight. I generally like smaller, non bulky watches so that I can wear them in all conditions (I also always have the urge to know what time it is).

    Thank you and great review!!!

    1. Author

      Hi Jackson. If you want a sports watch with date and time, there are a few that I can recommend for you (you can read their reviews by clicking the links embedded on it).

      1- Japanese automatic diver’s watch – these are the cheapest high quality automatic watches that money can buy: Seiko watches (SKX007, SKX009, Monster, Turtle) or Orients (Mako II, Ray II)

      2- Swiss watches – if you want to have that Made In Swiss watches: Hamilton Khaki King and Khaki Pilot

      3- Citizen’s Eco-Drive – Solar powered watches means you will never need to change its battery ever: Eco-Drive Perpetual Chronograph and Eco-Drive Blue Angels watch

      4- Tissot T-Touch Expert Solar – a very tool like sports watch with touch screen features

      Let me know if you have any further questions buddy.


Leave a Reply

Your email address will not be published. Required fields are marked *