Seiko 5 Sports SBSA027 Made In Japan Dive Watch

The Seiko 5 Sports collection introduced in 2019 presented not only quality timepieces at an affordable price point, but also a wide range of styles.

In this review, I’ll be taking a closer look at the Seiko reference SBSA027, a steel dive watch with a solemn black dial contrasted by a dual-material rubber strap. Most notably, and as is denoted by its model number, this SBSA027 is manufactured entirely in Japan.

Follow along via the following categories.

  1. SBSA027 Watch Specs
  2. Case & Bezel
  3. Dial
  4. Fused Strap
  5. Movement
  6. On-The-Wrist Review

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Seiko 5 Sports SBSA027 Specifications

  • Style: Specialist
  • Case Diameter: 42.5mm
  • Case Material: Stainless Steel
  • Crystal: Seiko Hardlex
  • Water Resistance: 100M / 330ft
  • Dial: Flat Black, Lumed (Green LumiBrite)
  • Bracelet: “Fused” Faux Alligator & Rubber
  • Movement: Seiko 4R36, Automatic
    • 41-Hour Power Reserve
    • Day & Date
    • Hacking/Stop Seconds Function
    • Wind via Crown
  • Retail Price: $350
Seiko SBSA027 Black Dial Close Up

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Seiko SBSA027 Case Dimensions

The Seiko 5 Sports SBSA027 is marked by a stainless steel case that possesses a 42.5mm diameter, 46mm lug-to-lug measurement, 13.4mm in thickness, and 22mm strap size (between the lugs).

Not merely a sterile steel case, SBSA027 boasts a dual finish: the flanks of the case are in high polish and the top is a satin or brushed finish. The crown guards are also polished, and the lugs possess lug holes which makes changing the strap incredibly easy and convenient, though I’m not sure you’d want to skip on this fused strap. I’ll be going into more detail on this strap further into this review.

Seiko SBSA027 Diver Stainless Steel Case & Crown Details

Atop the case sits a unidirectional knurled bezel, also in steel. It possesses a diver’s scale insert that is black with silver calibrations.

Protecting the face of the watch is a scratch-resistant and shatter-proof Seiko Hardlex crystal. Between the crystal and the bezel is a slight channel or divide which adds an attractive bit of texture and is reminiscent of older diver’s watches that had acrylic crystals.

This being a diver’s style watch, the SBSA027 is rated to 100m of water resistance. This is less than the standard 200m depth rating that most “professional” dive watches tout. Nevertheless, it should not deter you from wearing the watch in aquatic environments such as the pool or ocean.

SBSA027 Black Dial Details

Taking a closer look at the face of the Seiko SBSA027, we can see the dial is a flat black color and is surrounded by silver minute markings. Applied onto the dial are also polished hour indices with green luminous fills (Seiko LumiBrite.)

Black Dial Luminous Hour Indices On SBSA027

The hands at center are likewise presented in high-polish steel construction with a generous amount of lume. The seconds hand is also steel though half of it has been painted black to improve contrast.

Made In Japan Black Dial Seiko 5 Sports SBSA027At the traditional 3 o’clock position is a wide rectangular day-date aperture; it reveals the discs that display black font on a white background. This being the Made in Japan model, the languages of the Day are English and Japanese (Kanji).

It’s also worth noting that there is some small print at 6 o’clock that indicates this SBSA027 is made entirely in Japan. This same model is available in a non-Made in Japan (international market) version under the reference SRPE21; the differences between international and Japanese market models are merely cosmetic and include this minimal dial printing. The performance of the movement and overall design of the watch are exactly the same.

Fused Rubber & Alligator Strap

One of the most notable aspects of this SBSA027 is its dual-material strap. The base of the strap is black silicone that has been hollowed out on its top to make way for an alligator component.


While the stitched alligator component may not be genuine alligator hide, it nevertheless imparts a formal ethos to the strap and overall look of the watch. The strap remains very flexible so the comfort is in no way compromised. The strap is also marked by a Seiko-branded stainless steel tang buckle and matching silicone keeper.

SBSA027 Powered By 4R36 Movement

The movement powering this SBSA027 is a self-winding (automatic) Seiko 4R36 caliber that can be observed through the sapphire case back. The 24-jewel movement possesses the following technical features:

  • 41-hour power reserve
  • +45/-35 seconds/day accuracy
  • Day-date complication
  • Hacking seconds (stop seconds)
  • Hand-winding via crown

SRPE21 4R36 Seiko Movement Caseback

Of note from this list of features is the stop/hacking seconds function. Previous value-oriented Seiko dive watches did not possess movement with a hacking seconds function. This allows the user to set the time quite accurately as the seconds hand will stop ticking when the crown is pulled out to position 2 (the time-setting position).

Additionally, the 4R36 caliber permits winding of the movement via the crown at position 0. This also entails that the crown does not screw into the case; this is likely what led to the decreased depth rating. Nevertheless, the hand-winding function is incredibly convenient and a worthwhile tradeoff for the 100m of water resistance.

Seiko 5 Sports SBSA027 Overall Review

Of the formal styles that exist within the Seiko 5 Sports collection, the SBSA027 is one of the most subdued yet most refined examples.

The dial possesses the traditional Seiko diver aesthetic that, upon closer inspection, proves to be very detailed precise. The case, while a larger diameter than I generally prefer, wears its dimensions very compactly; by no means does this wear as an oversized watch, nor is it so small that it may go unnoticed.

SBSA027 Steel Seiko Watch On Rubber Strap

Broadly speaking, with the 5 Sports collection Seiko sought to update and modernize the beloved Seiko SKX watch and, with examples such as this SBSA027, I believe they’ve accomplished this goal wholeheartedly.

The only disadvantage inherent to the SBSA027 specifically is the fact that you may find yourself paying a premium for this model, the Made in Japan version. This is because some collectors place a higher value on Seiko watches that are manufactured within Japan. However, as mentioned earlier in this review, this watch is also available in an international market version so, if you settle on this 5 Sports iteration, you can purchase it for significantly less than the $350 MSRP.

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"A subtle yet refined dive watch within the popular Seiko 5 Sports collection. If you're searching for an affordable and Japan-made Seiko style, the SBSA027 should be on your radar."
Bespoke Unit Rating: ★★★★★

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