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Dive into the Details of Seiko Prospex PADI SBDC121
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Dive into the Details of Seiko Prospex PADI SBDC121

A thorough inspection of Seiko special edition timepiece on overall appearance and movements
Mar 22, 2021

Seiko is perhaps best known and appreciated for its diver's watch and automatic gear. Seiko makes some of the best automatic watches in the world in its price range. Especially the dive watch which is popular among watch enthusiasts. Watches offer a very high value for money. One of them is the Seiko Prosper X Padi Automatic SBDC121 watch.

Seiko is still at the top of the list when it comes to a value proposition in an automatic dive watch.

Prospex SBDC121 PADI Turtle, hugely popular since its release in 2016 as part of the famous “Turtle” 6105/6309 reissue, is no exception. Just as it is picked up from the 70's, the SBDC121 is relatively inexpensive, reliable, and tested for professional use. Perfect for vacations, weekends, and pools, this summer review of the potential modern Seiko classic is in the line.

This watch is a serious dive watch and tool from Seiko that offers all the things mentioned, and more.

But is SBDC121 really as good as people say?

Seiko SBDC121 review

The Seiko SBDC121 is a limited-edition timepiece designed by Mae to commemorate Seiko's partnership with the Professional Association of Diving Instructors, or PADI.

This watch is large, sporty, sturdy, but has a unique and attractive color tone. Its bright and bold color is what makes a watch that has been loved and loved even more special.

SBDC121 is almost identical to this standard version of Turtle, reference SRP775. It has the exact same dimensions, weight and motion.

What collectors and enthusiasts alike love most about this watch is the fact that you can enjoy the vintage-inspired aesthetic of a dive watch, but do so in a modern, durable and reliable form and shape, without having to worry about breaking it ( or that something will break). This watch was released in 2016 as a special edition, but despite being a modern timepiece, it looks vintage.

With watch collection at a high level today, thanks to the digital age and the simultaneously increasing value of the vintage market, the recent trend of major brands releasing "reissue" watches to conjure up the greatness of the past has significantly increased. In most cases size has become an issue, as modern versions usually have larger cases. However, the SBDC121 matches its predecessor Seiko 6309 with a sturdy 45mm x 13.5mm bearing-style stainless steel case (lug-to-lug is 47.5mm). This bracelet is 22 mm wide at the lugs and tapers up to 20 mm at the clasp. It's great fun and wearable at this size but as someone with a wrist under 7 inches, he wears a little bigger than ideal for this writer's preference.

PADI is one of the most trusted scuba diving training organizations, and as such, the partnership between this organization and Seiko with its professional dive watches makes sense. If the watch was approved by them - experts, it would be good enough for anyone.

The Seiko Prospex Padi SBDC121, true to its predecessors, has a dial, index, pointer and date display layout similar to that of the ancient Turtles. The "Pepsi" color scheme has always been a collector's favorite, and the mix of the blue sunshine pattern dial, the minute / hour hand marker highlighted in red, and the red / blue diver's bezel do well.

Let's take a look at this watch in more detail.

The Seiko SBDC121 Case

The Seiko SBDC121 features a 45mm bearing style stainless steel case. The shape of this casing is what collectors now call "turtles".

The history of turtles dates back to 1977 when Seiko released the first turtles. This watch is very similar to the SBDC121. Affordable, durable, good looks, long lasting. What else can you ask for?

The case itself is familiar to many of Seiko's other dive watches, so this is nothing new. It has drilled holes in the lugs that allow easy replacement and replacement of the spring bars. In terms of practicality, drilled lugs are very valuable. From aesthetic point of view, they split the onion.

Next, the top of the casing is brushed in a circular pattern. This adds to finishes such as tools and watch faces. The case's sides are polished, creating a pleasant contrast.

45mm is the larger size, but thanks to the relatively short lugs, the wear is smaller than shown on paper. The case has a classic crown position at 4 o'clock, separately integrated into the case. The crown is 7 mm in diameter. The crown placement provides more comfort than the traditional 3 o'clock position because it prevents the crown from slipping into the wrist. It is interesting to see that Seiko did not make a crown protector, but instead integrated the crown into the casing to protect it. Crown guards are not required for this model, and the case protects very well. The crown is screwed, of course.

The case also features a unidirectional rotating bezel, considering it's a dive watch. To improve readability, it has a luminous pip at 12:00. Multicolored aluminum inserts contribute to a fun and attractive aesthetic, with the first 20 minutes red and then the rest blue. The bezel also has a clear, easy-to-read indicator. The complaint that some people have reported is that some examples don't have aligned bezels. This means that the position will be slightly wrong. It is repairable and under warranty, but at this price, we feel that it is exactly what you would expect for a watch in this price range.

The case has a magnetic resistance of 4,800 A/m, according to Seiko.

The watch is equipped with Seiko's Hardex crystal like many other Seiko watches. At this price point, sapphire crystal is not widely used due to its high price. Plus, Hardlex crystals have been shown to be much more durable and scratch resistant than standard mineral glass.

The back of the case is the tough etched and embossed back of the case for optimal resistance and protection against water and leakage.

As a diving watch, it has a water resistance of 200 meters. It is quite wearable when swimming and even diving. In addition, this watch meets ISO 6425 standard for diving watches.

Seiko Prospex Padi SBDC121 Movement 

The automatic and mechanical 6R35 movement powers the Seiko Prospex Padi SBDC121. It is a 24 jewel watch machine with a power reserve of 41 hours when fully wound. This gesture displays the hour, minute, second, day, and date.

This movement is a self-winding caliber with a capacity for manual winding and hack seconds. It beats at 3Hz (21,600 vph).

This movement proved to be a hard worker. This movement was introduced in 2011 and was very reliable and precise. Plus, it's also durable and strong. Exactly what you expect and need from a movement built into a sporty dive watch.

Dial of Seiko Padi SBDC121

Without using too many fuzz words, we can say that the SBDC121 dial is quite beautiful. The dial has a stunning sunburst dial in blue that reflects light beautifully and provides rich depth. At 3 o'clock, we have Seiko's iconic day and date window which of course serves a practical purpose. Moving on to markers, which are painted, not applied. Markers are treated generously with Seiko's Lumibrite which means the watch shines strongly and offers good readability in low-light conditions. On the outside of the dial, there is a "ramp" with a white minute marker and a red 5 minute marker. The little red details match perfectly with the red on the bezels and also look good when compared to the blue.

Thus, the colors blue and red have earned him the nickname "Pepsi".

Lastly, the minute hands are also made in red to match the watch's theme. The triangular minute hand on a blue background provides good readability.

The dial layout of the Seiko Prospex SBDC121 is nearly identical to that of its predecessors.

The special edition co-created with PADI (Professional Association of Diving Instructors) is also growing to fame. For more than fifty years, PADI has been the most trusted scuba diving training organization in the world. PADI has issued more than 25 million certifications and has done extraordinary things to promote diving to the world, making it a very attractive dive watch partnership with divers and collectors alike.

On the dial, we also have some printing. First, there is the Seiko logo at the top. Then underneath is the Prospex logo. Below the center of the hand is the PADI logo (note that this watch is a PADI special edition). Just below that, you have automatic printing and then a depth rating. Yes, the watch has a fair amount of print on the dial, but on the one hand, it doesn't feel like much. Yes, the dial could have been made less cluttered, but in a sense, we didn't want to erase anything because every piece of text or logo has an important place and represents something.

What is interesting to note about this watch is the fact that the iconic Prospex "X" logo printed on the dial is very special. This is the first time Seiko has used this logo in an affordable watch. The Prospex logo reminds us that this is a watch with professional specifications.

Seiko SBDC121 Strap

This watch has a stainless steel band with a double-fold locking button and diver extension, unlike the regular Pepsi SRP779, which comes with a black rubber case.

This watch has a total weight of grams with a metal bracelet. The good news is that thanks to the wheel holes, you can easily and easily switch to rubber straps or nato straps if you feel the metal band is too stiff or bulky. Many people choose to customize their watches with rubber straps for comfort and appearance.

This bracelet is 22 mm wide at the lugs and tapers up to 20 mm at the clasp.


The Seiko Turtle SBDC121 Prospex X Padi is truly an impressive tool and dive watch that offers great value for money. It's qualitative, powerful, solid, supported by automatic movements, and more. This watch also has an interesting and interesting history, as well as great visuals.

You shouldn't expect Rolex quality or a Patek Philippe finish, but given what you get and considering the price, there is no denying that this dive watch is one of the best dive watches for money on the market.

In the tradition of Seiko's watches, even the cheapest models were produced by Seiko himself. The overall quality, considering the $ 550 USD MSRP, is excellent. The case was made exactly as expected of Seiko. The bezels, even with the previously mentioned QC chapter ring alignment issues, are sturdy and durable. The bracelet, although not up to the Rolex Oyster standards, is, of course, sturdy and well designed. The details of the dial, hands and case, have been very well thought out.

Price and Perks

The SRP Turtle incorporates Prospex's famous "X" logo on the dial, one of Seiko's most affordable to own. With a price tag of under $ 600 and meeting ISO 6425 dive watch specifications, the Seiko SBDC121 should be considered an overall winner in an affordable dive watch.

Overall, it's a fun and great watch that you should consider buying.

Explore more collections from Seiko: Gnomon Special Highlight This Week: Seiko 5 Sport Lineup

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