Seiko Prospex “62MAS” SBDC101 (SPB143) Watch Review

Posted by Nick L. on May 26, 2021

More often than not, if you ask a watch collector what the catalyst for their watch obsession was, it was an entry-level Seiko diver. I won’t rehash what has been reported countless times before, but most agree that the charm and value for money can’t be understated.

The model that drew me in was the so-called Monster series. Seiko’s divers were so unconventional as to feel special despite their low price. You didn’t feel like you were buying them because they were a cheaper look-alike of the watch you really wanted but couldn’t afford. The Monster, with its offset crown and chunky stainless steel bezel epitomized that.

Seiko hasn’t always been this way, however. Their first professional diver model, the 62MAS, actually looked quite conventional. It’s style mimicked that of other so-called skin divers that were becoming popular in the 1950s and 1960s. Given the craze for vintage reissue watches, it’s no surprise that Seiko has also visited its back catalog. The SBDC101, or SPB143 as it’s known in Japan, is one such model, and the one that I purchased for review. So does a more conventional and also more expensive Seiko diver still capture the charm that got us into this hobby? Let’s find out.

First Impressions

Although it loses all of the funky charm of a Monster, the SBDC101 really does “pop” in the metal. It is the Seiko that has grown up as I have since I started this hobby 10+ years ago. Even though it looks much more like the dictionary definition of a dive watch, Seiko employs a number unique, albeit more subtle design touches to give the new 62MAS its own identity.

The main feature that you’ll notice is the stainless steel bezel insert with a black coating. I tends to take on a ceramic look, but in certain light you can see that it is actually brushed metal. This construction, combined with the white painted numerals really sells the watch. At a time where every modern dive watch is moving to ceramic inserts, and vintage-inspired pieced have stuck with glossy anodized aluminum, the stainless gives the watch something unique.

Additionally, the sunburst pattern on the gray dial combined with the raised and polished indices give the watch a more expensive look than you’ve come to expect from Seiko divers.

The case and bracelet feature a mix of brushed and polished finishes, which are accentuated by the Dia-Shield super hard coating. It gives a slightly extra bit of gloss to the look, plus helps to resist against find scratches from daily use.

Wearing the 62MAS

Seiko’s divers tend to be on the chunky side, but for the 62MAS, Seiko kept the case diameter to a restrained 40.5mm. The size is slightly larger than the original, but is right in the sweet spot for this more grown up and modern diver. In additional to being more comfortable, it makes the watch more versatile. It’s a watch that you could wear to a business meeting on the bracelet, and then throw on a rubber strap and take it to the gym.

As Seikos tend to do the SBDC101 wears very well. The curved lugs, and contoured case shape make it very comfortable. It’s 13.2mm thickness is also respectable for a 200m diver. Polished chamfers also mean that the bushed sides of the case band reduce the visual thickness of the watch.

The Fine Details

In addition to the beautiful dial mentioned earlier, the SBDC101 (unlike many Seiko divers) features a very  traditional. This was a common modification on previous 62MAS reissue watches, and it looks like Seiko got the message. They even went one better and applied a half-brushed, half-polished finish to the hands, ensuring that they are easy to see against the dial in any ambient lighting.

Helping make the watch easy to read, as any Seiko fan would expect, the SBDC101 features Seiko’s excellent Lumibrite lume. Bucking the recent trend, Seiko used green pigment, rather than moving to blue color like it has with other models. I find the whitish-green slightly brighter and easier to see at night, so it’s a welcome direction.

Speaking of lume, the version pictured here features a minor update over earlier versions of the same watch. The new versions of the 62MAS, as well as other Seiko divers now have a lume marker at 3 o’clock. Some watches move the location of the date window, or, as with the 62MAS, squeeze in the lume on the minute track. The version without looks a bit more elegant, but I like having the extra lume (and having the latest version).

The 101’s crystal is ever so slightly raised above the height of the bezel, almost giving the look of a boxed crystal. The benefit of this is that it gives the watch some character without adding thickness. The downside is that you still don’t have the nostalgia effect of a fully boxed crystal, yet you have a bit of it’s distortion. Finally, I like how the result straddles the line between modern and vintage.

Seiko collectors will also be familiar with the fold out dive extension on the bracelet. In the case of the SBDC101, the clasp is improved, with machined hardware rather than stamped steel. The links and clasp feature an attractive mix of polished and brushed finishes. Drilled lugs make swapping out for your favorite strap easy as well (other options from StrapHabit are shown in some of the photos).


One of the bragging rights that Seiko collectors are quick to point out (to anyone who will listen), is the fact that they have in-house movements. A big jump in price is typically needed to retain that claim from a Swiss brand. Other than being in-house, and very reliable, however, there was nothing special about the movements in those older Seikos that we loved. They lacked even hacking or hand-winding, and the finishing was agricultural at best.

Luckily, to keep up with the price increases, Seiko has been slowly upgrading its movements. Moving from the 7S series in the original Monsters, the 4R series of movements added hacking and hand-winding. The 6R15 then added a Spron hairspring and other upgrades, increasing power reserve from 40 to 55 hours and improving the accuracy.

To help justify the $1,200 price tag, the SBDC101’s movement has received further upgrades. Seiko uses the 24 jewel 6R35 in this series. It still beats at a slower 21,600vph, but features a 70 hour power reserve. It is listed as accurate to +25 to -15 seconds per day. A smoother seconds hand sweep, and instant date change like an ETA 2824 would be nice, but the power reserve increase is a more practical upgrade.


In the past, cheap Seiko dive watches were always sold based on their bang for the buck. People were willing to put aside a few quirks because the watches were so inexpensive. But gone are the days that you can buy a Seiko dive watch for $150. The latest Monster will run you $525 at MSRP, and at $1,200 MSRP, the SBDC101 is yet another level up from that. Does it pack a corresponding increase in quality?

I was impressed with the watch when I first received it. It really is the perfect size, and Seiko nailed the proportions and styling. It also features a number of upgrades that provide real value over lower-priced Seikos. The SBDC101 features a slightly domed sapphire crystal with AR coating on the underside. The finishing is also much nicer, and protected by the Dia-Shield coating. Additionally, the 6R movement with its 70 hour power reserve is a big step up from the 7S movements of the past.

Unfortunately, after wearing it around the house for a little while, I did start to notice that some of the minor QC issues of entry Seikos are still present here. The bezel requires a bit of finesse to get it to line up, the bracelet rattles and little, and still the crown is not signed. My enthusiasm started to fade a bit.

But then I wore it out and about on a trip. Seeing in the daylight, and wearing it in public made me see the real value of this watch. You stop noticing the minor minutiae and start feeling like you have  a much more expensive watch strapped to your wrist.

Finally, the sum of the Seiko’s parts add up to an enticing package, so much so that I recommended it when a friend asked me to recommend a $1,000 watch to give to his step son at his graduation. I believe that this was the best choice because of its good looks, versatility, and the fact that it should never go out of style. This is a Seiko diver that you’ll buy not because its funky and affordable, but because it’s a beautifully made, and attractive looking watch.

Your Thoughts?

What do you think of the SBDC101/SPB143? Can you name a better dive watch for around $1000? We’d love to hear it in the comments.

And if you enjoyed this review, please check out the straps on our website and follow us on Instagram @strap_habit. Your support helps us to continue to bring content like this.


  • Name: Seiko Prospex “62MAS”
  • Reference Number: SBDC101 (Japan SPB143)
  • Price: $1,200
  • Dimensions: 40.5mm diameter, 47.6mm lug-to-lug, 13.2mm thick, 20mm lug width
  • Movement: Seiko Caliber 6R35
  • Water Resistance: 200m
  • Crystal: Domed sapphire with clear AR coating on the underside
  • Crown:  Screw-down
  • Bezel: Stainless steel with brushed stainless steel insert, and Dia-Shield coating. Unidirectional, 120 clicks
  • Strap/Bracelet: Stainless steel with Dia-Shield super hard coating


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