Seiko Prospex “Mini Tuna” Safari Edition SUT403 & SUT405 Watches Review

Seiko Prospex “Mini Tuna” Safari Edition SUT403 & SUT405 Watches Review

Taking one of their most important professional dive watches, extracting all its important architecture and functionality and adding more contemporary colours and textures, Seiko have transformed their iconic Tuna watch into two new Seiko Prospex Mini Tuna Safari Editions under references SUT403 and SUT405.

The new Seiko Prospex Mini Tuna Safari Editions are part of the Japanese watch brand’s Street Series collection, a family inspired one of their most innovative diving instruments, the 1975 Seiko Tuna. The historic design remains renowned as not only the world’s first divers watch with a titanium case but as Seiko’s most distinguishing case design named after its large diameter and bold profile shaped like a tuna tin.

For the SUT403 and SUT405 models, however, the prefix “Mini” has been added to the legendary nickname to mark its slightly more efficient architecture. This is not to be confused with the “Baby Tuna” which like other Tuna models measures to around 47mm but comes with shorter lugs for an arguably more streamline and compact finish.  The Mini Tuna, on the other hand, measures in significantly smaller with both Seiko Prospex Mini Tuna Safari Edition watches measuring to 38.7mm in diameter, 40.4mm in height and 10.35mm in width.

Like the Seiko Street Series watches before it, the Seiko Prospex Safari Edition references deliver the same signature bezel shroud with two-toned colourway, a 60 minute diving scale, box shaped applied indexes and luminous hands for central hours, minutes and seconds. The colour scheme of the SUT403 and SUT405 models are also incredibly similar to those seen in the “Urban Safari” series launched last year with rather stealthy, military-inspired colours making their way across the bezel, dial and strap.

The Seiko Prospex Mini Tuna Safari Edition watch under reference SUT405 comes dressed in a very safari-like khaki green with a green dial, rubber strap and unidirectional bezel. Reference SUT403 is a little more nautical with a navy blue colourway complemented by matching beige Lumibrite indexes and hands and a gold 20 minute increment on the 60 minute diving scale. Other than their colour schemes, both designs follow suit with the same 3.87mm case size, stainless steel architecture, screw in crown and case back, Hardlex crystal glass and water resistant rating of 200 metres.

Housed within each Seiko Prospex Mini Tuna Safari Edition watch is the V131 solar powered quartz movement. This isn’t the first time we’ve seen a Seiko Tuna fuelled by light, nor is it the first Street Series watch to do the same, however the legendary toughness and practicality of their solar powered calibres are widely favoured in their diving instruments. The V131 movement can be recharged using both natural and electric light and delivers a 6 month power reserve in total darkness and promises an impressive accuracy of ±15 seconds per month.

We have no doubt that like similar designs before it, the Seiko Prospex Mini Tuna Safari Edition SUT403 and SUT405 watches will be instant favourites with Seiko collectors. Ultimately, they have taken their most emblematic and most robust divers design from the 1970’s and adapted it for a smaller, more contemporary wrist allowing it to be worn just as effortlessly in the water as on land with a pair of jeans and trainers.

If you’d like to learn more about the new Seiko Prospex Mini Tuna Safari Edition watches and shop your own, head over to the Jura Watches website here. You can also get in touch with the team on 01335 4534543 or send us a message at

Specifications: Seiko Prospex Mini Tuna Safari Edition Watches (SUT403, SUT405)

  • Case Size: 38.7mm
  • Case Material: Stainless steel
  • Bezel: Unidirectional
  • Glass: Hardlex crystal
  • Crown: Screw in
  • Case Back: Screw down
  • Water Resistance: 200 metres
  • Movement: V131 solar quartz
  • Functions: Hours, minutes, seconds
  • Power Reserve: 6 months when fully charged
  • Accuracy: ±15 seconds per month
  • Dial: Khaki green or navy blue with Lumibrite hands and indexes
  • Strap: Silicone
  • Buckle: Pin
  • RRP: £470

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