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Seiko Prospex Turtle (SRP777) Review: The Ultimate Diver's Watch for Enthusiasts

Seiko Prospex Turtle (SRP777) Review: The Ultimate Diver’s Watch for Enthusiasts

by Thomas Jentzsch on April 5, 2023

The Seiko Prospex Turtle (SRP777) has been an iconic timepiece for decades, earning a loyal following among watch enthusiasts and divers alike. With its distinctive design, robust build, and reliable performance, the Prospex Turtle has more than earned its place in the horological hall of fame. In this comprehensive review, we will explore the ins and outs of the SRP777, from its history to its features, comparing it with other popular watches in the market and providing valuable insights to help you make an informed decision.

Brand Summary

Seiko, a Japanese watchmaking powerhouse founded in 1881 by Kintaro Hattori, has built a reputation for producing high-quality, reliable, and innovative timepieces at various price points. With a history spanning over a century, Seiko has continually pushed the boundaries of horological technology, introducing the world's first quartz watch, the Astron, in 1969, and later, the revolutionary Spring Drive movement.

Watch Details

The Seiko Prospex Turtle, with the reference SRP777, was first introduced in 2016. However, its design lineage goes back to the 1970s with the legendary Seiko 6309 diver’s watch. The 6309, nicknamed the Turtle due to its cushion-shaped case, was a popular and reliable diver’s watch produced from 1976 to 1988. The modern Prospex Turtle line pays homage to this classic design while offering modern upgrades and improvements to meet the demands of today’s watch enthusiasts and divers.

The SRP777 is part of Seiko‘s Prospex line, which stands for “Professional Specifications.” This series is designed for sports enthusiasts, adventurers, and professionals who need a rugged, reliable, and high-performance timepiece. The Prospex Turtle is available in various color schemes and finishes, with the SRP777 model featuring a black dial and bezel with stainless steel case and bracelet or a silicone strap option.

The Seiko Prospex Turtle SRP777 is powered by the Caliber 4R36 automatic movement, offering a 41-hour power reserve and hacking and hand-winding capabilities. It features a day-date complication at the 3 o’clock position, providing additional functionality for users who appreciate having these features readily available. The watch is ISO 6425 certified, ensuring its reliability and performance as a professional dive watch.

The price range of the Seiko Prospex Turtle SRP777 is typically between $300 and $450, depending on the retailer, condition, and whether you opt for the stainless steel bracelet or the silicone strap. It is widely available through authorized dealers, online watch retailers, and second-hand marketplaces like eBay and Watchuseek. Due to its popularity, the SRP777 can sometimes be found at a discount, making it an even more attractive option for those on a budget or looking for a great value in a dive watch.

One of the standout features of the SRP777 is its distinctive cushion-shaped case, which measures 44.3mm in diameter and 14mm in thickness. While the case size may appear large, the watch wears comfortably on various wrist sizes due to the case shape and relatively short lug-to-lug distance. The stainless steel case provides a robust and durable construction, ensuring that the watch can withstand the rigors of daily wear and professional diving activities.

The unidirectional rotating bezel is a crucial feature for any dive watch, allowing divers to keep track of their elapsed time underwater. The SRP777’s bezel is adorned with a 60-minute scale and features a luminous pip at the 12 o’clock position, ensuring legibility even in low-light conditions.

The dial of the SRP777 is protected by Seiko’s proprietary Hardlex crystal, which offers a good level of scratch resistance and durability. Although not as scratch-resistant as sapphire crystal, the Hardlex crystal is more shatter-resistant, making it a suitable choice for a rugged sports watch.

In terms of water resistance, the Seiko Prospex Turtle SRP777 is rated for up to 200 meters (660 feet), making it suitable for recreational and professional diving. The watch features a screw-down crown at the 4 o’clock position, which helps to improve water resistance and prevent accidental adjustments underwater.

Overall, the Seiko Prospex Turtle SRP777 combines a rich history, robust construction, and reliable performance into an attractive and affordable package. Its versatility, durability, and iconic design make it an ideal choice for watch enthusiasts and divers alike.

Key Features

  • Automatic mechanical movement: Caliber 4R36
  • 41-hour power reserve
  • ISO 6425 certified dive watch
  • Water-resistant up to 200 meters (660 feet)
  • Unidirectional rotating bezel with a 60-minute scale
  • LumiBrite hands and markers for superior legibility in low light conditions
  • Day-date complication at 3 o’clock position
  • Screw-down crown at 4 o’clock position for improved water resistance
  • Hardlex crystal for scratch resistance and durability
  • Stainless steel case and bracelet or silicone strap option


PRO (+)

  • Iconic design with a rich history
  • Reliable automatic movement
  • ISO 6425 certified dive watch with 200 meters water resistance
  • Excellent value for money


  • Hardlex crystal is not as scratch-resistant as sapphire crystal
  • Cushion-shaped case may not be to everyone’s taste

Comparable Watches

When looking for alternatives to the Seiko Prospex Turtle SRP777, a few comparable watches come to mind in terms of quality, features, and price.

The first is the Orient Ray II, a popular automatic dive watch from another well-respected Japanese brand. With its in-house movement, 200 meters of water resistance, and a day-date complication, the Ray II shares many similarities with the SRP777. However, its sleeker design may appeal to those who find the Turtle's cushion-shaped case too distinct.

Another worthy alternative is the Citizen Promaster Diver (BN0151-09L), powered by Citizen's Eco-Drive technology, which uses solar energy to recharge the watch's battery. Like the SRP777, the Promaster Diver boasts a water resistance of 200 meters and features a unidirectional bezel, luminous hands, and markers. It does not have a day-date complication, but its solar-powered movement means it requires little to no maintenance, making it an excellent option for those who value convenience.

For a Swiss alternative, the Tissot Seastar 1000 Powermatic 80 is an attractive choice. With its Swiss-made automatic movement, 80-hour power reserve, and 300 meters of water resistance, the Seastar 1000 boasts impressive specifications. The design is more refined than the SRP777, with a sleeker case and more intricate dial details. However, the Tissot Seastar 1000 comes with a higher price tag, often retailing for around $600-$700.

Watch Collectors Opinions

The Seiko Prospex Turtle SRP777 has received overwhelmingly positive reviews from both watch enthusiasts and professional divers. Many praise its robust build, reliable performance, and the fact that it stays true to its iconic 1970s design roots. Some reviewers have noted that the Hardlex crystal, while durable, is not as scratch-resistant as sapphire crystal, which is often found on more expensive dive watches.

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The Seiko Prospex Turtle SRP777 is an excellent choice for watch enthusiasts and divers seeking a reliable, functional, and iconic dive watch at an affordable price. Its history, performance, and design make it a worthy addition to any watch collection. While there are comparable alternatives available, the SRP777's unique combination of features, heritage, and value make it stand out from the competition.


Q1: Is the Seiko Prospex Turtle SRP777 suitable for professional diving?
A1: Yes, the SRP777 is an ISO 6425 certified dive watch, making it suitable for professional diving activities.

Q2: Can I replace the Hardlex crystal with a sapphire crystal?
A2: While it is technically possible, replacing the Hardlex crystal with a sapphire crystal may void the warranty and should only be done by an experienced watchmaker.

Q3: Does the SRP777 have a manual winding feature?
A3: Yes, the Caliber 4R36 movement in the SRP777 supports both automatic and manual winding.

Q4: What is the lug width of the Seiko Prospex Turtle SRP777?
A4: The lug width of the SRP777 is 22mm.

Q5: Can I swap the bracelet or strap on the Seiko Prospex Turtle SRP777?
A5: Yes, the SRP777 features a standard 22mm lug width, allowing for easy strap or bracelet replacement with various aftermarket options to suit your personal style and preferences.


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