Casio GA-2100: The Outstanding CasiOak Watch

In 1983, Japanese watchmaking brand Casio created their first-ever G-Shock timepiece, the DW-5000. The DW-5000 showcased Japanese technology, reliability, and hardy longevity. A few years after its release, Casio released the AW-500. This timepiece was notable for being the first G-Shock analog model to come into existence. While bearing G-Shock’s trademark durability, the AW-500 also had a unique and bulky exterior that screamed toughness.

Fast forward to today, and Casio’s G-Shock lineup is filled to the brim with all sorts of rugged timepieces. Out of all of the recent releases, one particular G-Shock model stands tall. In 2019, Casio unveiled the G-Shock GA-2100. Sometimes referred to as the CasiOak, the GA-2100 quickly became an unlikely favorite of the watch community. Let us take a more detailed look at the GA-2100 and why people just cannot seem to get enough of this watch.

All About the CasiOak

The CasiOak assembly consists of a number of models. For this article, we will be focusing on the Casio G-Shock GA-2100-1A and its exclusive features. 

front view of Casio G-Shock Ref. GA-2100-1A watch
Image By: G-Shock

Carbon Core Guard Case

Casio watches are known for their oversized builds. As such, it should not come as a surprise that the CasiOak GA-2100-1A has some bulk to it. This watch has a case dimension of 45mm and a thickness of 11.8mm. It measures 48.5mm lug-to-lug and has a lug width of 16mm. Despite its rugged aesthetics, this CasiOak model weighs a light 51g, making it comfortable to wear and easy to bring around. This is all thanks to the case’s Carbon Core Guard structure. The use of the Carbon Core Guard structure gives the watch the same formidable resistances as a traditional G-Shock while also ensuring a more lightweight build.

For those not so familiar with the concept, the Casio G-Shock Carbon Core Guard Structure is a formula Casio uses for their newer G-Shock watches. It enables the brand to attain the perfect harmony between sturdiness and size. By reinforcing its resin cases with carbon fiber, Casio is able to strengthen the exteriors of its cases while also toning down its overall girth and weight. The CasiOak GA-2100-1A uses this same Carbon Core Guard principle but showcases it in an octagonal form, with an octagon-shaped case and bezel. Printed on the bezel are the “G-Shock” and “Protection” signatures, along with function labels that indicate the purpose of each pusher.

As you turn the CasiOak over, you immediately see its stainless steel case back. Screwed-down for maximum protection, the rear case is engraved with the “Carbon Core Guard” signature, along with the Casio name and some other information on the G-Shock model. As with all G-Shock watches, the resin material of the case protects this CasiOak watch from all kinds of shocks and impacts. It also has a substantial 200-meter water resistance rating. This allows the CasiOak GA-2100-1A to withstand everything from rain to ocean water.

Design-wise, you can immediately see that this watch bears some resemblances to Audemars Piguet’s world-renowned Royal Oak. Casio, however, insists that they derived the design from their own 1983 and 1989 models, the DW-5000 and the AW-500. Whatever it is, you cannot deny the looks of the CasiOak GA-2100-1A. It carries an aesthetic that blends the durability we love from Casio G-shock watches with a hint of Gerald Genta sophistication. Casio also pairs the GA-2100-1A with a matching resin band that is integrated into its case. 

Multidimensional Dial

The work on the dial, for a lack of a better term, is exceptional. It has a three-dimensional look that highlights each component on the dial surface. Its minute indices take the form of understated cuts etched around the rim. The hour indices, on the other hand, are bulkier and protruding and have a light grey hue. It boasts a neat set of sword-shaped minute and hour hands mounted on a slight elevation that, in turn, gives more depth to the watch face.

All versions of the CasiOak GA-2100 contain two unique features: a day display at 9 o’clock and a digital screen between the 3 o’clock and 6 o’clock positions. The layout of the CasiOak GA-2100 is quite ingenious, as it manages to fit all its complications on its dial without making it look cluttered or messy. The day display takes the form of a small indicator that points to the seven days of the week, which are etched inside a narrow semi-circle. The digital screen is intriguing, as it bears an irregular rhombus-like shape. The digital display is compact enough to fit its allocated space while also providing legible texts and numerals.

One downside to the CasiOak is that the brand only added luminescence on the watch hands. As such, the overall lume quality is quite underwhelming. Personally, it would have been neat to have the hour markers coated in lume as well. That said, the CasiOak does come with LED light and backlight features. These provide the CasiOak GA-2100 with sufficient sources of brightness and legibility in dark times environments.

Mineral Glass

For such an affordable watch, mineral glass is pretty much what you would expect. The budget-friendly crystal provides a clear view of the watch face and offers a decent amount of protection from scratches. In addition, wearers can easily buff out any scuff marks with the help of some polish, a soft buffing cloth, and elbow grease. If the crystal becomes too obscure due to excessive damage, you can also replace the mineral crystal quite cheaply.

Casio 5611 Module

The CasiOak GA-2100-1A uses a 5611 quartz movement. For a G-Shock watch, this caliber provides a moderately limited set of features: digital and analog time, full-auto calendar up to the year 2099, hourly time signal, five alarms, countdown timer, stopwatch, and world time. The 5611 caliber is powered by two SR726W batteries that can last up to three years. In terms of precision, it has an accuracy of +/-15 seconds a month. On the whole, the CasiOak has a pretty basic slew of functions compared to other G-Shock models. That said, it is still a highly functional watch with handy functions that offer wearers a lot of convenience in their daily routines.


The CasiOak GA-2100-1A, in particular, can cost you around $99 USD. Depending on the model purchased, the CasiOak can fetch a selling price of up to $250 USD. Some pre-owned versions do also come with a slight discount, depending on the seller and the condition the watch is in.  

CasiOak Variants

Since its launch in 2019, the CasiOak GA-2100 lineup has become home to several diverse and colorful models. Currently, CasiOak has a catalog of 15 different watches in total. For you to have a better idea of what the range looks like, here are a few distinct, fan-favorite CasiOak models that would make great additions to your collection.

1. GA-2100-1A1

front view of Casio G-shock Ref. GA-2100-1A1 watch
Image By: G-Shock

The G-Shock GA-2100-1A1 is arguably one of the most popular variants in the CasiOak selection. With an all-black aesthetic, from its dial and case to its resin brand, the GA-2100-1A1 comes off as an edgy and contemporary G-Shock timepiece. While its dark looks appeal to the eyes of many, it also has some design flaws. For instance, when you bring the CasiOak GA-2100-1A1 into a dark environment, the dial can be a little hard to read. Even with luminescent material coated on its hands, the watch face is still not very legible in poor lighting conditions. Fortunately, this CasiOak watch is packed with LED lights, so it can illuminate itself if necessary. Aside from the legibility of the watch face, however, the GA-2100-1A1 brings everything the CasiOak series promises — ruggedness, durability, and sophisticated style.

2. GA-2100-4A

front view of Casio G-shock Ref. GA-2100-4A watch
Image By: G-Shock

Here is another highly recognized CasiOak GA-2100 model. Red throughout, this timepiece is quite eye-catching and a true sight to behold. The genius of this model lies in how Casio managed to make each shade of red stand out without looking too uniform. According to the brand, Casio used a total of nine different shades of red for this G-Shock watch. The CasiOak GA-2100-4A is a testament to the brand’s knack for integrating simple designs with creativity, practicality, and lots of charm. 

3. GA-2100HC-2A

front view of Casio G-shock Ref. GA-2100HC-2A watch
Image By: G-Shock

For a stylish and adventurous-looking CasiOak, have a look at the GA-2100HC-2A. Unlike the models mentioned above, this CasiOak watch does not utilize Carbon Core Guard Structure. Instead, it uses white and blue transparent resin for its case and integrated band, giving the GA-2100HC-2A a theme of marine exploration. The contrast of white, silver, and blue hues make this watch highly legible even in the dark. This allows it to double as a fantastic dive watch. The CasiOak G-Shock GA-2100HC-2A is an affordable and reliable watch for thrillseekers who thrive on underwater adventures.

4. GA-2100-5A

front view of Casio G-shock Ref.  GA-2100-5A watch
Image By: G-Shock

Another fascinating two-toned timepiece is the CasiOak GA-2100-5A. At a glance, the GA-2100-5A features a dark dial with a beige watch case and wristband. With both colors put together, they make up a CasiOak model that bears a tasteful yet rugged design. If the GA-2100HC-2A is fit for aquatic expeditions, then the GA-2100-5A is made for exploring deserts and arid landscapes.


Not so sure what to feel about CasiOak watches? Not a problem! Listed below are some alternative timepieces that not only possess similar qualities to the GA-2100 but also sell at relatively affordable prices. 

Luminox Bear Grylls Survival Sea Series 3729 – $495

front view of Luminox Bear Grylls Survival Sea Series 3729 watch
Image By: Watch Shopping

For our first alternative, we have the Luminox Bear Grylls Survival Series 3729. Although it is a little more expensive than any CasioOak model, this Luminox timepiece comes with its own set of brilliant qualities that is well worth the price. 

Where Casio uses Carbon Core Guard for their watch case, Luminox utilizes their iconic CARBONOX material. As with the Carbon Core Guard, Luminox’s CARBONOX takes advantage of the abundance and durability of carbon. The use of CARBONOX gives this Luminox Bear Grylls watch a rugged look and unparalleled durability that can take on any challenge.

Both the Casio GA-2100 and the Luminox 3729 also possess similar water resistance ratings of 200m. Each of them also uses mineral glass to shelter their respective dials. That said, Luminox uses a hardened mineral crystal, which is hardier and more resistant to hard impacts. Another thing the Luminox 3729 excels in is battery life. The Luminox 3729 can last 50 months, which is 14 months more than the 3-year battery life of the CasiOak. 

Exclusive to the Luminox 3739 is a unidirectional rotating bezel. As a diving watch, this bezel insert contains a time scale for divers to measure their elapsed time underwater. This timepiece may not have a day indicator like the CasiOak, but it does have a date function at 3 o’clock. Hidden below the dial of the Luminox 3739 is a Ronda 515 movement. This is protected by a solid 316L stainless steel rear case.

Maurice Lacroix Aikon – $1,990 USD

front view of Maurice Lacroix Aikon watch
Image By: Watch Shopping

The CasiOak, in itself, is a more accessible and casual version of the Audemars Piguet Royal Oak. If you want a more luxurious alternative to the CasiOak that only costs a fraction of the Royal Oak, there is no better option than the Maurice Lacroix Aikon. Encased in 39mm of stainless steel, the Aikon comes with a matching Maurice Lacroix stainless steel bracelet. With its blue tapisserie dial, elongated hour markers, silver sword hands, and date aperture at 3 o’clock, the Aikon exudes opulence similar to the famed Audemars Piguet watch. 

Unlike the CasiOak and Luminox Bear Grylls Survival Series 3729 which run on quartz calibers, the Maurice Lacroix Aikon is operated by a mechanical movement. The caliber is known as the ML115. It is a self-winding clockwork based on the Sellita SW200-1. It can produce 28,800 beats per hour (4Hz) and has a power reserve that, when fully wound, lasts up to 38 hours. Protecting the ML115 caliber is an exhibition-style case back, so wearers can view the movement while it operates. In terms of design, the Aikon is almost spot-on, with the main difference being the claw-like structures on its bezel and its composition, which is not quite as octagonal as the CasiOak. It also has a depth rating of 200m, so you can easily take this timepiece for a swim too.

Final Thoughts

For a $99 watch, the CasiOak GA-2100-1A offers a whole lot of enjoyable perks with only a few flaws. It does so in a robust and genuine style that we do not regularly see in a traditional G-Shock. One improvement that Casio could consider making to this watch is with regards to its lume, which is a little lacking.

Realistically speaking, coming across a timepiece identical to this Casio G-Shock watch along with all its features and price would be exceedingly rare. It just goes to show that Casio, as a watchmaking brand, is one-of-a-kind and in a league of its own. As for their CasiOak watches, it is (mineral) crystal clear why everyone wants to get their hands on this rugged yet lovely piece of G-Shock craftsmanship.

Looking for a watch to end all your watch hunger? Have a look at one of Patek Philippe’s greatest pieces, the Patek 5970.

Featured Image By G-Shock

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