Seiko Sea Urchin: A Review on One of Seiko’s Best Automatic Divers

Aug 14, 2020
Seiko Sea Urchin: A Review on One of Seiko’s Best Automatic Divers

Seiko Monster, Sumo, Tuna, and Turtle — ask any collector about these very familiar names and almost always they would tell you they owned one or even all of them at some point. All of which are Seiko’s affordable divers that are greatly adored by enthusiasts all around the world. These ‘beater watches’ exhibit the true value of the Seiko line. With the solid construction and gorgeous looks of these watches, they sure are worth every single penny.


And now, we’re highlighting an affordable diver watch that completes any and all collections: the iconic Seiko Sea Urchin from the Seiko 5 family.

The Seiko 5 Criteria

Released in 1963, the aptly named Seiko 5 collection requires 5 specific criteria that showcase the quality of timepieces the brand creates. Enthusiasts refer to the Seiko 5 with various names with the watches’ movements having 17 to 25 jewels.


There are a few innovations that trace back to the birth of Seiko 5. Firstly, there’s Seiko’s response to the Swiss Incabloc system called the ‘Diashock’. Secondly, Seiko’s unbreakable mainspring ‘Diaflex’ saw its beginnings with the Seiko 5. Lastly, Seiko figured how to make their timepieces water-resistant.


Seiko created these standards to provide quality timepieces without breaking the bank. In the beginning, these requirements include the Diashock system and the Diaflex mainspring. The watches must have a day/date window as well. And of course, a Seiko 5 watch must be water-resistant and self-winding.

front view of Seiko 5 Sports Watches
1. Seiko 5 Watches

Conversely, these have since changed into a more general rule of thumb to follow. At the 50th anniversary of the collection, they released new standards. Among those include an automatic winding movement. It should also have a day/date window and a recessed crown. With this, the watch must also have impeccable water resistance. And of course, a trait Seiko never failed to deliver, it must have a durable bracelet and case as well.


All Seiko 5 watches must meet these criteria to belong under the collection. And inarguably, the Sea Urchin does just that and a whole lot more.


Now, you might confuse the Seiko Sea Urchin with the Seiko SKX007 and SKX009, but they sure differ in many ways. Yes, they’re both classic dive watches. However, the Sea Urchin deserves its own merits for its notable qualities. We’re going to focus on the models SNZF17 and SNZF15, the most popular Sea Urchins in the market to date.

A Quick Look at the Seiko Sea Urchin

As aforementioned, the Seiko Sea Urchin meets all the Seiko 5 criteria. These assure the quality of the watch we’ll be reviewing today. However, there’s more to this watch than meets the eye. Here are some of the features that you should look out for:


  • Seiko Calibre 7S36 Automatic Movement
  • Water resistance of up to 100m or 330 feet
  • Scratch-resistant Hardlex mineral crystal
  • Uni-directional bezel
  • 41mm diameter; 13mm thickness
  • 46mm lug to lug distance; 22mm lug width


These aren’t the fanciest components you’ll see in a watch but they are, indeed, the greatest you can get at a modest price.

Review on the Seiko Sea Urchin (SNZF15/SNZF17)

1. Case

At first glance, the Seiko Sea Urchin definitely has the most iconic traits among Seiko’s dive watches. You’ll get just about the same with any diver with little variations. For instance, the Sea Urchin is a bit bulky and sits on the bigger side of the scale with its 41mm case. A lot of divers consider this just the right size for a dive watch, giving it more space for the necessary information. Its features also make it easier to handle and operate even when underwater. On the other hand, it’s not as hefty, so people with more delicate wrists wouldn’t be too daunted wearing it. With a thickness of 13mm, it’s surprisingly very slim for a dive watch. This feature alone makes it a comfortable accessory.

  • Material

Right at the touch, the Sea Urchin feels durable. Its robust case and design make it a reliable companion underwater. The watch is also great for its price range. It has an all-steel exterior. And by that, we mean from the case down to the bracelet, all exposed parts are steel. A lot of watches in this price range go for folded metal links that aren’t as durable. Additionally, the watch features a Hardlex mineral crystal to protect its dial and caseback. Speaking of which, you might want to take a peek at the back of the watch. The caseback provides a window to the movement as it works.

  • Lugs

Each watch has a 22mm lug with 46mm of lug to lug distance. The lugs have a brushed satin finish that contrasts the sides’ polished finish. This gives it a luxurious feel despite its overall sporty look.

  • Crown

A crown guard protects the push-pull crown at 3 o’clock. It’s recessed into the case that affects its water resistance. The grooves of the watch make it easier to grip and operate even when wearing gloves.


Moreover, the watch’s water resistance sits safely at 100m or 330 feet. Considering the watch’s price, this is already pretty impressive. It’s definitely a steal! You can take it for a recreational swim or snorkeling, but not for scuba diving. You’d want better water resistance for that. Don’t risk your Sea Urchin for a deep underwater dive!

  • Bezel

The 60-minute unidirectional rotating bezel helps the wearer keep track of elapsed time. The Sea Urchin may not provide the greatest grip on the bezel, but it definitely works well. There aren’t any misalignment issues either on both SNZF15 and SNZF17 — a usual concern among watches within this price range.  The SNZF15 has a Pepsi bezel, while the SNZF17 has a black bezel.

front view of Seiko 5 Sea Urchin Ref. SNZF15K1 watch
2. Seiko SNZF15K1 Sea Urchin

2. Dial

For starters, the Seiko Sea Urchin has all the necessary information and reading it indeed is a swift process. The most noticeable part is the large hour indexes that contrast greatly with either the blue (SNZF15) or black dial (SNZF17). These markers, a tad raised, resemble the Rolex Submariner, which may be the greatest inspiration for the watch. Reading the time in dimly lit places shouldn’t be a problem as the broad hands and markers are all covered in lume.


There are various inscriptions on the watch such as the ‘5 Sports’ emblem. It also displays the given water-resistance of the watch as well as the words ‘AUTOMATIC’ and ‘23 JEWELS’ in reference to the watch’s movement. These inscriptions fit just right within the timepiece’s aesthetic without cluttering the dial with unnecessary information. Meanwhile, the watch’s day/date window has discs that match the dial colour. This adds coherence to the watch for a more aesthetically pleasing experience.


At a glance, the watch is almost comparable to how a Rolex Submariner fits for any function. Both the Seiko SNZF15 and SNZF17 are great watches, but the SNZF17, with its black bezel and dial, compels an easier choice. Take it to a suit and tie event or a weekend dive and it will be just as useful as it is stylish.

front view of Seiko 5 Sea Urchin Ref. SNZF15 watch
3. Seiko SNZF15 Sea Urchin

3. Bracelet

To complete the watch’s robust and sporty aesthetic, it boasts a 22mm three-link stainless steel bracelet with removable end links. Secured with a triple-lock clasp, the watch’s bracelet shows the quality Seiko watches stand out for. The watch offers an option for a NATO-style strap that would appear friendlier in the water. It’s also a bit more comfortable, yet the steel bracelet doesn’t depart far from that as well.

4. Movement

Seiko proves time and time again that they can provide automatic watches at an affordable price range. The brand creates one of the most budget-friendly options, especially for those who are just starting to collect watches. Despite the price, each Seiko watch performs well with reliable and durable overall engineering.


A lot of Seiko divers and entry-level Seiko 5 watches have the calibre 7S36 automatic movement in them. First released in 1996, the movement is the obvious affordable choice for the brand. It has hours, minutes, seconds, day, and date functions. Moreover, the movement bears 23 jewels. It also vibrates at about 21,600 beats per hour. In addition, the watch has a power reserve of about 41 hours or more. It may not be the most expensive watch out there but it’s certainly one of the best for its price.

Final Thoughts

The Seiko 5 Sea Urchin (either SNZF15 or SNZF17) presents itself with the greatest things you can have for its price point. It’s a stylish and affordable option if you’re looking for a watch that comes close to the feel of the Rolex Submariner. Given that most of its parts are reminiscent of the iconic Rolex, this timepiece should be every new collector’s must-have.


While it is inspired by the said Rolex watch, it’s safe to say that the Seiko Sea Urchin is a timepiece that deserves rightful credit. It is timeless, durable, and of course, reliable. As a sports watch, it is indeed a great choice for an entry-level timepiece that you can take even beyond the waters.


Loved the Sea Urchin? Check out our guides to the Seiko Turtle, Monster, Sumo, and Tuna.


Photo credits – Amazon and official Seiko website

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