Seiko Turtle SRPE93 Review: The Cult-Classic Dive Watch For Under $500

The Seiko Prospex SRPE93, the most recent version of the legendary Seiko Turtle dive watch, hit the market relatively recently, in 2021, but its lineage can be traced all the way back to the 1970s. What makes this defiantly retro-looking tool watch such a favorite of enthusiasts even today? There’s a lot more to it than the very accessible price point, as we’ll explore here in this in-depth examination — or, a look under the shell, if you will —  of the SRPE93 “Turtle.”

Seiko, the world’s oldest and most established Japanese watchmaking brand, was one of the pioneers of the dive-watch genre and it has long stood apart from its Swiss contemporaries in this field (i.e. Rolex, Blancpain, and others) for its use of bold and unconventional designs. One of its most off-the-wall and yet most enduringly popular designs is the original "Turtle” — aka, Ref. 6306 and 6309 — which made its debut in 1976. The former reference was made exclusively for the Japanese market (and thus, vintage examples are much rarer and more valuable), and the latter was sold to international customers. The reptilian nickname derived from the watches’ cushion-shaped cases with softly rounded lugs, which brought to mind the silhouette of a turtle when viewed from above. The reference numbers for the watches essentially matched those of their automatic movements — Caliber 6306A, which included hacking seconds and Caliber 6309A, which did not. 

The Turtle’s unusual look and rugged construction, with 150 meters of water resistance, found an appreciative audience in the ensuing years. It gained a greater level of pop-culture visibility when actor Ed Harris wore it in the 1989 underwater-adventure film The Abyss (above), and the model has also been spotted on the wrists of legendary rockers like Mick Jagger of the Rolling Stones and Brian May of Queen. However, perhaps the chunky and somewhat quirky case of the original Turtle was a little too off-the-wall for some buyers even in the 1970s, an era renowned for wild experimentation in watch design, as Seiko offered a more understated and conventionally shaped version in 1982. 

The Ref. 6309-729A, aka the “Slim Turtle,” was produced until 1988 and featured a rounded, more sharply angular case — some might say, a redo that didn’t really live up to the Turtle nickname. Despite its relatively short production run, the “Slim Turtle” provided the template for what would become the most enduringly popular Seiko dive watch ever, the now-discontinued Ref. SKX007 (above). As for the original Turtle design, it faded from the market for a time, making way for an array of variations on the SXK007, but it made a triumphant return in 2016 as part of a major re-brand by Seiko of its Prospex line of tough, stylish, sport-oriented watches.

That watch was the Ref. SRP777, the direct antecedent of the SRPE93. In most respects, it was a very faithful revival of the now-cult-classic 6309, with a handful of mostly technical upgrades, including the use of a more modern automatic caliber, the Seiko 4R36, and an increased water resistance of 200 meters. Aesthetically, the black dial touts this increased depth rating and also replaces the original model’s “150M” text with the stylized “X” that the maker uses to identify models in its Prospex series. In addition, the solid caseback has the somewhat perplexing “Air Diver’s 200M” inscription, which may or may not refer to the “air” in a diver’s tank. 

Seiko Turtle SRPE93 Case and Bezel

What needs to be said about the case of the Seiko Prospex SRPE93 that hasn’t already been mentioned? Following in the grand tradition of its “Turtle” ancestors, the modern Prospex version of the case measures a hefty 45mm in diameter, with a lug-to-lug span of 47.7mm and a thickness of 13.2mm. (The SRP777 was a tad smaller, at 44.3mm in diameter.) Because of those famous shortened lugs — the “legs” of the turtle, for lack of a better descriptor — many reviewers have opined that the watch wears a bit smaller on the wrist than these muscular dimensions might suggest. Made of stainless steel, the case has a brushed finish on its surface and polished facets on the sides. The screw-down crown that helps ensure the robust 200-meter water resistance is tucked away in the unconventional 4:30 position and sports prominent fluting for easy grip by hands in thick divers’ gloves. 

The dive-scale bezel, with its black aluminum insert, rotates in one direction, as per international dive-watch criteria, with 120 distinct clicks to set the dive times on the 60-minute scale. The 12 o’clock (or 60-minute) marker is designated by a luminous dot inside an inverted triangle. The crystal is made from Hardlex, Seiko’s proprietary mineral glass material, which is not as scratchproof as sapphire but more resistant to shattering under impact, which many prospective users would agree is a decent tradeoff for a rugged watch like this.

The solid caseback screws into the case, its matte surface emblazoned with a relief-engraved medallion depicting a tsunami, a longtime Seiko symbol applied to its divers’ watches. Along with this imagery, and differentiating the SRPE93 in another subtle way from the SRP777, is the inscription “Diver’s Watch 200M,” replacing the “Air Diver” on the earlier model. 

Seiko Turtle SRPE93 Dial and Hands

Evoking the legibility-first design of the 1960s and ‘70s divers that inspired this re-edition, the SRE93’s dial is in matte black, with white printed hashmarks on the minute track and an assortment of big, applied geometrical shapes for the hour markers — eight round bubbles, at the 1.2, 4, 5, 7, 8, 10, and 11 o’clock positions; two pointer-tipped wedges at 6 and 9 o’clock; a wider wedge bisected by a “sword” motif in the center at 12 o’clock; and a day-date window at 3 o’clock accompanied by a small luminous pip. It is this final detail that, despite its relatively subtle impact on the overall aesthetic, represents the most significant difference between the SRPE93 dial and that of its very similar predecessor, the SRP777, which had no pip next to the window; this reference added it in order to comply with ISO dive watch standards, which require low-light legibility at all the hour markers. The other consequence of this change was that the SRPE93 day-date window lacks the beveling around the edges that gave the SRP777 version a bit more depth.  

The handset is among the most distinct, emblematic features of the Seiko Turtle models, combining a wide, sword hour hand with a syringe-like tip; a similarly thick, arrow-shaped minutes hand; and a seconds hand with a round counterweight that appears, at a glance, to be a smaller version of the bubble hour indexes.

All those markers, along with the entirety of the hour and minute hand, the seconds hand’s counterweight, and the previously mentioned bezel pip, are coated with Seiko’s proprietary LumiBrite, which takes the base compound in Super-LumiNova — strontium aluminate — and adds europium and dysprosium for a luminous paint that Seiko claims absorbs light faster and glows for a longer duration after being activated. The Seiko logo appears in white type at 12 o’clock, and the Prospex “X” emblem is stacked above “Automatic” and “200 Meters.”

Caliber 4R36 Movement

The "Automatic" designation on the dial refers to the self-winding movement inside the case, Seiko’s in-house Caliber 4R36. A widely popular and fairly ubiquitous workhorse in Seiko’s mechanical-watch repertoire these days, it was introduced in 2011 and essentially replaced and superseded the Caliber 7536 movement by adding a hacking seconds function and hand-winding capability. Measuring 27.4mm in diameter and 5.32mm thin, Caliber 4R36 offers 24 jewels, a steady 3Hz frequency (21,600 vph), and a serviceable but not stellar power reserve around 41 hours. 

Seiko claims the movement achieves an average daily accuracy of +45/-35 seconds — again, not much to brag about, especially in light of the proven precision of other, higher-end Seiko (and Grand Seiko) movements, but certainly fine for an everyday-wear timepiece at this accessible price point. It’s probably why this movement is so popular as an outsourced engine for many other, often smaller watch brands that specialize in entry-level automatic watches. For those who obsess over such horological trivia, the 4R36 is the Seiko-exclusive version of this caliber, but in its un-branded NH36 version, it powers an array of other three-hand-date timepieces across the industry. 

Seiko Turtle SRPE93 Strap and Clasp

The Seiko Prospex SRPE93 secures its underwater bonafides with its black rubber silicone strap, which at 22mm wide nestles firmly into the stubby “turtle-leg” lugs. Its rippling ridged texture near the lugs give the watch an additional hint of tool-watch character, and the brushing and polishing of the buckle echoes that of the case. The use of such a strap leaves no doubt that Seiko intends this watch to be worn for diving or other active and adventurous pursuits; it would stand out like a sore thumb worn with a dress shirt or formal jacket, not that such a pairing would be unheard of in this day and age of look-at-me watch wardrobing. 

Pricing and Final Thoughts

The Seiko Prospex SRPE93 — aka the modern Seiko Turtle (not to be confused with the King Turtle, which we reviewed here) — retails for $495. Perhaps waiting until this wrap-up paragraph to mention that is an egregious example of burying the lede, but it could also be argued that it was best to drill down first into all the attributes this watch offers before pulling the curtain on the price. Needless to say, finding this combination of elements — classical heritage, retro charm, rugged build, iconic design, reliable in-house mechanical movement — at a price under $500 is rare indeed. The fact that it carries nearly as much historical dive-watch cachet as much loftier timepieces — with price tags to match — like a Rolex Submariner, Omega Seamaster, and Blancpain Fifty Fathoms, is a decided bonus. You can learn more at seikowatches.com.