G-SHOCK GBX-100 Review


G-SHOCK GBX-100 in the shade

The G-SHOCK GBX-100 watch wasn’t high on my “must have” list. G-SHOCK touts the model as a watch for fitness buffs and surfers. Since I’m neither a step-counter nor a wave-rider, I figured it wasn’t a watch for me.  After its release in May 2020, the latest in Casio’s “G-Lide” series sold out quickly, garnering nearly unanimous praise on the watch forums. When availability trickled back I decided to see what the commotion was about . . .

The first thing that jumps out: the Casio’s “MIP” display. Whereas a normal LCD depends entirely on a backlight and pixels (that refresh themselves every minute or so), a Memory In Pixel display includes an optical layer that reflects and transmits light to brighten the screen.

In bright light, it’s perfectly legible. In low light, it’s perfectly legible. The GBX-100’s transflective layer (transmissive + reflective) allows illumination from a backlight to light up the display.

G-SHOCK display comparison

How much better is MIP than its Casio competition? Check out the above comparo of Casio’s negative LCD displays. Left to right: STN (Super-Twisted Nematic), MIP (Memory In Pixel) and traditional LCD.

GBX-100 vs. GM510BC-1JF

Bottom line: you can read the MIP negative LCD display from the most obtuse angles, in any light.

My wife could read the time on the G-SHOCK GBX-100 from across the table in a dimly-lit restaurant. Try that with a traditional negative LCD display.

G-SHOCK GBX-100 at the restaurant table

Like its brothers in arms, the GBX-100 has multiple functional displays that take full advantage of the the high-resolution display.

In fact, the watch is so packed with functions, modes and information, I haven’t been able to delve into all of them, even after a full week of wear. Let’s hit the highlights . . .

The main time mode screen is easier to read than Bathtime for Biscuit. The date (month/day) appears in a smaller font in the upper right corner, large enough to read with my unaided 56-year-old eyes.

The day of the week lives in the lower left corner, projected in the same font size as the date. The activation status of various functions (DST, BlueTooth, Alarm, Signal, etc) appear in very small fonts along the bottom of the screen and in the upper left corner.

G-SHOCK tide and time indicator

The Tide and Moon Phase calculator is presented in three different display modes. The Tide calculator is available in a 12-hour or a 24-hour graph format. The tide display includes the moon phase and sunrise/sunset times in a smaller font. There’s also a dedicated moon phase display that includes sunrise and sunset times.

From what I can tell (comparing to the NOAA website), the high and low tide calculations were off by about 30 minutes in my area. (I didn’t have time to sit on the beach to see for myself.) Compared to what I can see in the night sky, the moon phase appears to be spot-on.

In reality, I have as much use for the tide and moon functions as an orthodontist has a need for the helium release valve on a Rolex Sea-Dweller. But it looks cool.

G-SHOCK GBX-100 fitness screens

The fitness calculator is the GBX-100’s other major feature. It has various functions, including timers, goals, stopwatch, etc.

Ye olde G-SHOCK Move App

The watch syncs with the “G-Shock Move” phone app. You can set up alerts for fitness goals met. Notably absent on the GBX-100: a heart rate monitor. That’s a deal killer for those hardy souls who sacrifice sweat on the altar of CrossFit.

From what I’ve gathered from watch forum chatter, none of the Casio step-counters are accurate. Word on the street: if you’re serious about using a fitness calculator on your wrist, get a “real” wearable like the models offered by Garmin.

G-SHOCK phone notifications

The G-SHOCK GBX-100 Bluetooths to your phone. Activate the notification function and the watch will beep and vibrate whenever your phone wants your attention (text, email, phone call, calendar alerts, etc.). The Casio keeps up to 10 notifications before the old ones roll off.

It’s a smartwatch Jim, but not as we know it. To read a text from my son required six button pushes. No matter how many times I pressed the buttons I couldn’t reply. After half a day of being more connected to my phone than I wanted to be, I turned off the notifications.

G-SHOCK surf's up!

The G-SHOCK GBX-100 is packed with features I’ll never use. Then again, maybe my new Casio will compel me to get off my butt to use the fitness functions. Or  hit the beach and “hang ten.” Or go fishing – where I’ll find meaning in the tide and moon phase and perhaps even life itself.

Meanwhile, the GBX-100’s killer MIP display makes it a worthwhile watch. I don’t think I’ll ever buy another traditional negative LCD watch.

Model: G-Shock GBX-100-1
Price:  $160

Case:  Resin
Strap:  Resin
Dimensions:  50.9 x 46.0 x 14.7 mm / 66 g
Movement:  Module #3482
Battery life: 2 years with CR2032
Water resistance: 200m (660 ft)

Time Functions:  Digital hour / minute / seconds, date, day, stopwatch (1-sec), countdown timer, Four daily alarms with snooze, 12 / 24 hour format, World Time (29 time zones / 38 cities), hourly time signal, auto-light.

Tide / Moon Functions:

  • Moon data (moon age of the specific date, moon phase).
  • Tide graph (tide level for specific date and time).
  • Sunrise, sunset time display.

Training Functions:

  • Display of distance, speed, pace, and other calculated values based on accelerometer, auto/manual lap times, Auto Pause, target alert setting (time, calories burned) on/off, training display customization (elapsed time, distance, pace, lap time, lap distance, lap pace, average pace, speed, average speed, calories burned).
  • Training Data (Up to 100 runs, up to 140 lap times per run) Elapsed time, distance, pace, calories burned.
  • Life Log Data – Daily data display (step count), Monthly data display (running distance).

RATINGS (out of five stars):

Design * * *
While a completely new model, the GBX-100 is a typical and recognizable G-SHOCK design. The shiny forged steel  bezel adds a bit of panache.

Legibility * * * * *
You can read the MIP negative LCD in any light, at any angle.

Comfort * * * *
Better than most G-SHOCKs. The band is soft and pliable, the strap holes closely spaced and fine adjustments are a doddle

Overall  * * * * *
Designed for fitness, fishing and surfing, it’s still a worthy timepiece for kooks and Barneys, thanks to the stunningly easy-to-read MIP display


TTAW is a fully independent watch website
No considerations were provided for this review.


  1. Finally some technology I care about, a worthwhile negative display! A quick googling reveals that Garmin and a few other smart watches use MIP, but I’d love it to come down to the low end dumb ones. Finally I know what the point of that tide display stuff is. I thought is was for flood watch or something.

    • The tide information is useful for boaters, fishermen, and surfers. I believe the moon phase is useful to them, as well, though I cannot expound on the reasons.

      It just occurred to me that the moon phase would be useful for emergency personnel at fire stations, police, and emergency rooms…. full moon = crazy people come out to play.

  2. Shocked to be reading about a G-Shock but great to know about the MIP development in this quartz genre. Mr Racer88, I know you love watches but wearing 3 – wow! Respect.

  3. hi, great review on them gbx.. need help on the hourly signal though.. for the life of me, i couldnt find how to set the hourly signal on the gbx.. thanx in advance..

    • Hi Jerry. Thanks for the feedback on my review. I’m at the office and don’t have the GBX-100 on me at the moment. But, a quick scan of the manual… and I can’t find any reference to an hourly signal. It appears the GBX-100 does not have that function.

  4. I just ordered the g shock gbd 100 that have all you experienced but non of moon sun tied that I don’t need actually. And have a nicer design suit my 42 year on this rock… Thank

  5. I came across a hidden menu that has to do with the settings, I can’t remember how to access it again do you know how to and what other hacks do you know for the gbx100

  6. Sir,

    can you please upload more pics of protrek and the GBX? i want to know the viewing angle.

    i wanted to buy a protrek, i read it is an STN display. i have GBX and im afraid im not gonna like the STN display because of my experience with the MIP display.

    thank you.. 🙂

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