Seiko Turtle vs Mini Turtle – Dive Watch Comparison

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Seiko is a watch company based in Japan and is one of the most well-respected in the industry. The company began operation back in 1881 as a jewelry shop, but it was during 1924 when Seiko officially entered the watchmaking market. Known for innovations in the watch industry, Seiko kickstarted the quartz watch revolution of the 1970s. Their revolutionary watch movement forced the industry to evolve or be left behind and change the watch market did.

Seiko once again hit another milestone when they introduced the first solar-powered watch in 1977. The iconic Japanese watchmaker kept the ball rolling with outstanding timepieces to this day.

Seiko has also built a solid reputation in the dive watch market as seen from their Prospex watch line. This highly-rated collection from Seiko features some of the most popular names in the diving timepiece category such as the Turtle, Samurai, Sumo, and the Mini Turtle.

Each of these watch lines brings its specialty to the table that helps separate them from one another. The Turtle’s uniquely charming case, the Samurai’s aggressive design, the Sumo’s robust construction, and the Mini Turtle’s compact build.  

In this article, we will be taking a look at the Seiko Turtle and its smaller sibling, the Mini Turtle. Is the size the only difference between the two or are there more than meets the eye?

Seiko Turtle VS Mini Turtle

First, let us do a quick introduction to both of these Seiko dive watches. The Seiko Turtle is one of the brand’s most recognizable dive watch models. It is also a re-release of a classic Seiko dive watch that was released back in the 70s and 80s known as the model #6306 dive watch.

Of course, a reissued timepiece model needs to bring something new to become relevant as nostalgia can only get you so far. In this aspect, the Seiko Turtle most certainly delivered.

The Turtle features an ISO 6425 certification making it a legit dive watch. The turtle shell-shaped case further enhances the charm of this retro timepiece making it a worthwhile dive watch to hunt down.

The Seiko Mini Turtle, on the other hand, has a pretty self-explanatory moniker. It got its name for its resemblance with the Seiko Prospex SRP series, the Turtle. The Seiko Turtle, with its shell or cushion-style case, is a subject of contention for some customers as it can be rather cumbersome on smaller wrists.

Enter, the Mini Turtle that is a sleeker and more compact version of the beloved Seiko dive watch SRP model. Similar to the Seiko Turtle, the Mini Turtle is available in different color variations and are also available in stainless-steel bracelet or silicon strap models.

The SRP watch line’s case generally has a 45mm diameter size, the Mini Turtle comes in at 42mm while retaining that retro aesthetic. There is also a slight difference within the inner workings of these two Seiko Prospex timepieces.

The SRP Turtle features the caliber 4R36, while the Mini Turtle utilizes the caliber 4R35 watch movement. The main difference between these watch movements is that the 4R36 comes with both a day and date display while the latter only has a date display.

There is also another difference in design in the form of an embedded date magnifier in the Mini Turtle models. Both the Turtle and Mini Turtle feature ISO 6425 certification and provide 200-meter water resistance. Everything else is nearly identical.

We will be comparing two specific models from each Seiko Prospex line down below to help paint a clearer picture about what to expect between these two dive watch brands.

Seiko King Turtle SRPE07

Seiko SRPE07 Prospex Men's Watch Black 45mm Stainless Steel
Seiko King Turtle SRPE07 (Image: Amazon)

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The Seiko King Turtle SRPE07 might look like the typical SRP series model, but a closer inspection will yield some nifty tweaks that make this into one of the finest Seiko SRP offerings to date. General dial layout remains the same with other Turtle models, but the bezel is where the most noticeable changes lie. Rather than having a stainless-steel bezel, the SRPE07 is now made from ceramic which gives it a considerably higher scratch-resistance than the metal. Additionally, ceramic material will not be affected by UV rays from the sun, completely circumventing color fading issues.

The dial window also got a notable upgrade. Seiko Turtle watches typically use Hardlex crystal, the SRPE07 though took it a couple of steps further by implementing a sapphire crystal window. Sapphire crystal is widely used by the best watchmakers due to its innate resistance to scratches.

The sapphire window also features an embedded “cyclops” magnified section over the 3 o’clock position on top of the day and date display. The dial also brings its visual flair in the form of the wave pattern that perfectly complements the beautiful blue color tone.

When it comes to the inner workings of the SRPE07, you can expect the signature quality present in all Seiko Turtle watches. It utilizes the caliber 4R36 automatic hand-winding movement that gives this watch an impressive 21,600VPH, which translates to higher accuracy. The watch movement also provides the SRPE07 with a 41-hour power reserve when fully charged.

The Seiko Turtle SRPE07 retains the classic cushion-style case which measures 45mm with a thickness of 13mm. It goes without saying that the SRPE07 is a rather bulky boy.

Finally, this Seiko dive timepiece delivers that signature 200-meter water resistance with an ISO 6425 certification to boot. If you love the retro-style of the Seiko SRP series, but which it offered more in the way of high-grade material, the SRPE07 might just be the one you are looking for.

Seiko Mini Turtle SRPC39J1

Seiko Prospex SRPC39J1
Seiko Mini Turtle SRPC39J1 (Image: Amazon)

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As the name implies, the Seiko Mini Turtle is a more compact version of their popular Turtle SRP series. The standard SRP series watch features a 45mm case, the Mini Turtle, on the other hand, contains it within 42mm. Fortunately, the smaller build did not equate to a downgrade as the Mini Turtle can certainly hang beat-for-beat with its bigger sibling without any problems.

Design-wise, the Mini Turtle SRPC39J1 utilizes a rather quirky case that is somewhat similar to the cushion-style of the SRP series, albeit with a more confined and circular shape. The SRPC39J1 utilizes Seiko’s caliber 4R35 automatic 23-jewel hand-winding movement. It is quite similar to the 4R36, with the primary difference being that the Mini Turtle only has a date display rather than the day and date display of the larger SRP watches.

As noted earlier, the Mini Turtle features a more compact 42.3mm case with a height or thickness of 13mm. The watch also comes equipped with a 120-click unidirectional bezel which is made from aluminum. Along with the stainless-steel case and aluminum, the bezel is a Hardlex crystal window that comes with a built-in cyclops or magnifier for the date display.

We also liked the satin brush finish with a polishing combo done on the case which gives it a premium-grade look. The dial features a matte blue color tone which is a classic dive watch design. The hands have to use iconic Seiko design (arrow shape) and are coated with LumiBrite along with the hour markers.

Overall, the Mini Turtle SRPC39J1 is an excellent alternative to its larger sibling. It also delivers an ISO 6425 certificate with 200-meter water resistance, making it suitable for swimming, snorkeling, and even diving.


Now, let us go through a quick rundown of all the positives and negatives that come with the two Seiko dive watch models that we discussed above.

Seiko King Turtle SRPE07


  • It features a stunning polished blue dial with wave patterns that must be seen to fully appreciate.
  • Ceramic bezel adds to its overall premium feel while also providing the advantages that come with said material.
  • The dial window is made from scratch-resistant sapphire crystal material.
  • Despite the premium-grade quality materials, the SRPE07 has a reasonable price tag.


  • Some customers report that the SRPE07’s hour markers are slightly misaligned.

Seiko Mini Turtle SRPC39J1


  • Compact and quirky Seiko dive watch for those with smaller wrists.
  • The OEM rubber strap is flexible and comfortable.
  • The case features a nice finish that adds to its overall premium appearance.


  • The straps feel a bit cheap.

The Seiko Turtle SRP Series is one of the Japanese watchmaker’s most popular dive watch models and features a retro design that allows it to stand out from the competition.  However, the cushion-style case does equate to a bulkier build which can be an issue with individuals who have smaller wrists. This is where the Mini Turtle comes into play.

Nearly identical in all facets, but with a smaller frame, the Mini Turtle is a great alternative for the larger Turtle SRP watch.

Turtle vs Mini Turtle Specs – Comparison Table 


Seiko Turtle

Seiko Mini Turtle

  Seiko SRPE07 Prospex Men's Watch Black 45mm Stainless Steel Seiko Prospex SRPC39J1
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Model Number SRPE07 SRPC39J1
Watch Movement 4R36 4R35
Water-Resistant Rating 200-meter 200-meter
Case Diameter 45mm 42.3mm
Case Thickness 13.3mm 13mm
Band Material Silicone straps Silicone straps
Band Length 7/8-inches 25/32-inches
Band Width 22mm 20mm
Clasp Type Buckle clasp Buckle clasp
Dial color “Wave” Blue Blue
Dial Window Material Sapphire crystal Mineral crystal
Bezel function Unidirectional Unidirectional
Calendar Type Day and date Date
Special features Day and date display Date display
Item Weight 10 ounces 13.12 ounces