Seiko Prospex SRP639K1 Review & Complete Guide

Seiko Prospex SRP639K1 Review

It’s no secret that Seiko makes extremely durable and reliable at affordable prices. Seiko has a wide range of timepieces, but for watch enthusiasts, their sports and dive watches have the most appeal.

Seiko’s collection of sports and dive watches includes numerous timepieces, ranging from affordable to prices in the tens of thousands. One thing they all have in common, however, is that they offer exceptional value for money in terms of finish, reliability, and build quality.

Available from Amazon at a price of around 500 USD, the Seiko Prospex SRP639K1, also known as SRP639 really offers exceptional value for money.

Seiko SRP639K1 review

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The Seiko Prospex SRP639K1 is part of Seiko’s Prospex collection. What does this mean? It means that, as the name suggests, it is built according to professional specifications. This in turn means that it is built according to the needs and wants of professional divers. And what better proof of quality and reliability than being used and trusted by professionals? Because if it is good enough for them, it is likely good enough for you, too.

The Seiko Prospex SRP639 is built to last as a sporty and durable dive watch. But what is it that makes this watch so popular? Well, the first thing that makes this watch stand out about this timepiece is that it is different. Both in terms of design but also in its use of colors.

 In this article, we are reviewing and looking closer at the Seiko Prospex SRP639K1.

Seiko Prospex SRP639K1 case

The case shape of this watch is what is known by collectors as ”baby tuna”, as it is a smaller version of the larger model with the same case shape. This watch has later come to be known amongst enthusiasts and collectors as ”Yellowfin” baby tuna.

If you are a fan of the Seiko tuna case design but also have a hard time wearing large watches, this watch is the answer to your prayers.

Firstly, the iconic tuna shape is bold, different, and unique. This is a dive watch, but its design makes it look like no other. With this said, the almost round case with aggressive case details (shrouds) makes it stand out as a very sporty watch. The purpose of the ”shroud” is to work as a case protector/case guard to keep it well protected.

The case has a diameter of 45mm including the shrouds, but note that it will depend on how you measure the case. It is of course made in stainless steel, but as you can notice from the very first impression, it’s not like any other.

As we can expect from a sporty dive watch, the steel parts are satin-finished. And as a dive watch should, it has a unidirectional rotating bezel. The bezel is black and has no bezel insert. Instead, the 60-minute graduation markers are painted onto the bezel. The first 15 minutes are painted in bright orange color, whereas the rest of the markers are painted white. The bezel markings are broad and large which provides exceptional legibility. The case has a thickness of 13mm. It has a luminous pip and a yellow-painted triangle at 12 o’clock.

The case has a large crown which is positioned at 4 o’clock and slightly integrated into the case. Sitting on top of the case is a Hardlex crystal.

It’s also worth having in mind that despite the fact that it is smaller than the standard Seiko tuna size, it’s still a large watch.

As it is a professional dive watch, it of course has a serious water resistance, which in this case is 200m /660feet/20ATM. This makes it suitable for diving, swimming, and any other type of water sports.

Seiko Prospex SRP639K1 movement

The watch is equipped with a Seiko caliber 4R36. The movement is automatic and powered by a rotor. It has 24 jewels and has both manual winding and hacking seconds, both of which functions are not found in more affordable watches.

This movement is a reliable and sturdy workhorse movement that will continue to tick for years. And that is of course just what we want and need in a sporty dive watch. The movement is built to be able to handle knocks and bangs yet still continue to function, so you don’t have to be particularly careful when wearing this watch. After all, it is a sports watch.

Seiko Prospex SRP639K1 dial

What makes this watch stand out apart from the case shape and design is its color scheme. But it is important to note that whilst it uses a bright and bold yellow color for its accent, it is the only color It uses,  which means it doesn’t become too bright and crazy.

The watch has a matte black dial with an interesting design. The applied hour markers are huge and ”integrate” into the raised chapter ring around the dial. The hour markers have a generous amount of Lumibrite applied to them to provide exceptional legibility in low-lit conditions.

The hands too are large. The hour hand is arrow-shaped and painted white. The minute hand is painted yellow to match the color theme of this watch. It is sword-shaped and of course, has Lumibrite on it.

The seconds hand is matte black and has an arrow tip filled with Lumibrite and painted yellow.

All of these small details are extremely important for the overall look and visual appeal of this timepiece, and they go together exceptionally well to create an absolutely stunning timepiece.

Positioned at 3 o’clock, the watch has Seiko’s classic day and date window with a white background. This helps make the watch more practical since, after all, the vast majority of the time, you won’t be 100 meters down below the surface.

Photo: orbiter

Seiko Prospex SRP639K1 strap

The case has a lug width of 22mm and is presented on a black curved-end rubber dive strap which has a  buckle closure. The rubber strap has a quite nice quality and sits comfortably on the wrist. Plus, you cannot go wrong with a rubber strap on a diver watch.

The 22mm lug width also makes it possible to change straps as you please. It looks great on a large number of straps, and some owners have even chosen to put it on a steel bracelet to add additional sportiness to it.

SRP639K1 Specifications

• Diameter including shrouds: 45mm
• Lug width: 22mm
• Movement: Seiko Automatic in-house caliber 4R36
• Jewels: 24
• Thickness: 13mm
• Crystal: Hardlex
• Water resistance: 200M/660 feet
• Frequency: 21600 (6 beats per second)

Conclusion

If you enjoy sporty dive watches with a fun color twist and enjoy the Seiko Tuna case design, the Seiko Prospex SRP639K1 could be a watch for you. It has a bulky, unique, and sporty presence on the wrist. The discreet yet bold yellow accents add to the sportiness of this timepiece. 

This is a serious diver not only by looks but also in performance. And with all of these aspects in mind, including reliability, build quality, and finish, it also offers exceptional value for money too.

The Seiko Prospex SRP639K1 is available to order on Amazon.