The Casioak Goes Solar and Bluetooth! Has Casio Made My Dream G-Shock? GAB2100C-9A Watch Review

The Casioak Goes Solar and Bluetooth! Has Casio Made My Dream G-Shock? GAB2100C-9A Watch Review

 The Casioak Goes Solar and Bluetooth! Has Casio Made My Dream G-Shock? GAB2100C-9A Watch Review

When I originally reviewed the Casio G-Shock GA2110SU-3A (a.k.a. the Casioak), I said "to make this my perfect G-Shock, it would have solar charging, and atomic clock sync" but I was worried that adding those features would make the watch thicker and heavier. Well, my prayers have been answered - sort of! The latest Casioak models do have solar charging, although instead of atomic sync, they have Bluetooth connectivity. Has this made it the perfect G-shock? Keep reading to find out!

Although StrapHabit doesn't currently sell straps to fit this watch, you can view our favorite straps for your other watches at the links below
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Similarities to the original resin models

I've done Casioak comparisons of as many models as I have been able to get my hands on, including multiple resin colors the midsize versions in a few colors, as well as the metal cases in both sizes. Prior to this new solar version, my favorite, and the one that has stayed in my collection, is the blue metal GM2100N-2A. Since the GAB- models are only available in resin at this time, I'm going to compare to its closest analog (pun intended), the resin GA2100 and GA2110 models.

Right off the bat, my fears of the Casioak losing its desirable thin profile and light weight were unfounded. The addition of the solar panel and Bluetooth module only added a negligible 0.1mm of thickness, and 1 gram of mass. As far as a wearer can perceive, they are the same size and weight.

The Casioak Goes Solar and Bluetooth! Has Casio Made My Dream G-Shock? GAB2100C-9A Watch Review

I've already seen photos of people swapping modules between solar and non-solar models, meaning that the cases should be compatible.

EDIT: I later learned that this is only possible with the resin model, not the metal ones. See the follow-up article to learn more.

Additionally, adding these useful features has only added $50 to the price. Sure, that is a roughly 50% increase, but at $150 (or $160 for this yellow C-9A model), the watches are still a great value.

The differences

So as far as your wrist can tell, the new models are the same. So what's different (besides the obvious)?

As you might expect, the solar panel dials are dark gray on all of the new models. I know that other brands are able to do colored dial solar watches, but perhaps this would have made it thicker or reduced the charging performance.

Another difference seen on the dial is the display. While the original models displayed the day with a pointer, that has been replaced with a multi-function display. During normal operation, it shows the state of charge of the battery. It can also indicate when the watch is connecting to your phone via Bluetooth, or if you are using the Worldtime Stopwatch, Timer, or Alarm functions. As on the GMAS2100-4A, the day display has moved to the LCD screen. It can be selected to be shown in place of the date or current time, and on the GAB- models, reminder status.

The double LED illumination is also much brighter than the light on battery-powered ones. I assume that Casio is able to do this because there is no fear of the light draining the battery prematurely on models that can be recharged regularly by the sun.

The Casioak Goes Solar and Bluetooth! Has Casio Made My Dream G-Shock? GAB2100C-9A Watch Review

Also, at least at this time, all of the GAB- Casioaks have single-color resin cases (just the strap keeper is a contrasting color on this yellow model). I really liked the contrasting bezel color on the blue and green models that I owned, so hopefully, Casio will expand this. The black bezel of the yellow GA- model especially muted its bright appearance.

The Casioak Goes Solar and Bluetooth! Has Casio Made My Dream G-Shock? GAB2100C-9A Watch Review

The Casioak Goes Solar and Bluetooth! Has Casio Made My Dream G-Shock? GAB2100C-9A Watch Review

I do like that the buckle is black coated to match the accents on the watch, rather than the bare steel on some of the other models.


The yellow version

I only bought the yellow version at this time, so I can't comment on how the other colorways look in person, but I've been enjoying wearing this bright color as a fun summer watch. I've read others complain about the small blue and red text on the dial, but I think that it looks fun together with the yellow. It also replaces the WR 20BAR text seen on the originals in the same spot.

It's also possibly the most legible Casioak variant. The white/light gray hands and hour markers are similar to those of the black and white GA-2100-1AER, making the main time display a breeze to read at a glance. Additionally, this model has a positive LCD display (vs. negative on the -1AER), and the multi-function indicator is yellow, making it very easy to read. Add in the brighter LED lights, and it's a winner for legibility.

The hands have the same mediocre Neobrite lume as the other models, but the light and contrasting hands make up for it most of the time. Unfortunately, Casio didn't add its Auto-EL function to these models, which illuminates the display it if you tilt your wrist while in the dark.

I do feel that the resin on this model has a less premium look and feel than some of the other models. I haven't had one of the previous yellow models in my hand, but from photos, it appears to have a more matte finish than this version. Perhaps G-Shock needed to do this to make the yellow look extra bright, and separate it from the more matte GA- model. I'll have to get my hands on the other colors to see if this is a trend.

No atomic sync?

When the GAB2100 was first released, I was disappointed to learn that it would have Bluetooth connectivity rather than syncing to the atomic clock. I felt that it would be simpler to have the watch operate autonomously, and not have to worry about installing an app and connecting it to my phone.

After setting it up and using it though, I was converted. The Bluetooth time sync is much more reliable than me getting a signal from the Colorado atomic clock at my home in Ohio.

The watch actually does not remain connected to your phone all the time. Four times per day it will connect, sync the time, and then disconnect. It's pretty seamless and works better than I expected

Additionally, the watch has a "find my phone" function, and can record a location with the press of a button. You can also configure the watch, and set up alarms and timers via the app, which is much easier to do than remembering a sequence of small buttons to press.


Was I right when I said that adding solar and time-sync functions would make the Casioak the perfect G-Shock? I has definitely made it a more premium experience and added some useful functions. Unfortunately, I've also fallen in love with the premium look of my blue metal Casioak.

It looks like Casio has one more step to take to make the perfect G-Shock! Based on how it has been pumping out now Casioak variants, I'm guessing it's only a matter of time.

Your Thoughts

What would your perfect G-Shock be? We'd love to read about it in the comments.


  Original Solar/Bluetooth
Reference Numbers GA2100/GA2110 GAB2100
Available Colors Too many to name Black, Yellow, Blue, Green
Price (USD) $99/$110 $150/$160
Width (mm) 45.4 45.4
Height (mm) 48.5 48.5
Thickness (mm) 11.8 11.9
Module Number 5611 5686
Water Resistance (m) 200 200
Crystal Mineral Mineral
Weight (g) 51 52
Battery Life 3 years 7 months with no light


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Hi Kevin, thanks for your comment! Unfortunately, as I later learned, that’s not possible!


Swap modules so you can have your perfect Casioak!


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