Casio G-Shock GA-100 Watches

A typical representative of the round cases G-Shock and the record holder for the number of all kinds of colors and stylistic options, for which it is popular with modern youth. The case belongs to the category of “large” – 55 mm in height and 51 mm in width. Impact resistance consists of characteristic “influxes” on the front part that protect the glass from direct impacts and a step strap with pin mounting. Large buttons are conveniently pressed thanks to the ribbed surface and are protected from accidental pressing. In addition to resistance to mechanical damage, the watch has protection against magnetic fields. Ana-DJ dial is an ideal combination of information content and ease of reading data. Despite the low price, the GA-100 is equipped with a very accurate stopwatch for 100 hours, a timer with auto-repeat, world time, an alarm clock and a simple speedometer that works in conjunction with a stopwatch [you must specify the distance in advance]. Auto backlight will be activated in the dark when the clock turns to face.

Important Information

  • Price — 70$ *average Amazon Price, we may earn commission from purchases
  • Year of first Release —  2010
  • Module Number — 5081 / Manual
  • Model Range — GRAVITYMASTER (Developed in response to pilots’ needs, these tough watches offer improved accuracy, strength and practicality. Famous for unique and beautiful aviation design (usually analog) and advanced technologies.)
  • Battery Type — CR1220 (G-Shock Batteries)

GA-100 Model Range *may be updated

The most distinctive specs of GA-100 *Editorial
— 200-meter water resistance
(good for swimming but not for deep diving)
— Speed measurement (if you know the distance, you will know the speed in your watch)
— ISO 764 class magnetic resistant (A magnetic-resistant plate is mounted on the module. The plate prevents magnetic fields from interfering with proper movement of the hands in daily use)

Official Marketing Focus from Casio

Introducing a collection of new G-SHOCK models whose 35mm diameter faces and large cases give them a look of power and strength.
Dial rings and raised hour markers create three-dimensional depth that gives the face plenty of character.
The popular G-SHOCK three-dial face design incorporates one analog dial in the center, with digital dials on either side.
These watches are designed and engineered to deliver outstanding shock resistance and water resistance, as well as anti-magnetism.
Over-sized buttons come with a checkered anti-slip surface to make operations fast and sure.
1/1000-second stopwatch, velocity indicator, World Time, 5 alarms and much more provides these models with unmatched function and performance.

Official GA-100 Specs / Features *for base version GA-100-1A1

  • Case / bezel material: Resin
  • Resin Band
  • Magnetic Resistant
  • Shock Resistant
  • Mineral Glass
  • 200-meter water resistance
  • LED light
    Auto light switch, selectable illumination duration (1.5 seconds or 3 seconds), afterglow
  • World time
    29 time zones (48 cities + coordinated universal time), daylight saving on/off, Home city / World time city swapping
  • 1/1000-second stopwatch
    Measuring capacity: 99:59’59.999”
    Measuring modes: Elapsed time, lap time, split time
    Others: Speed (0 to 1998 units / hour), Distance input (0.0 to 99.9)
    Mach indicator (speed exceeding 1225 units / hour)
  • Countdown timer
    Measuring unit: 1 second
    Countdown range: 24 hours
    Countdown start time setting range: 1 minute to 24 hours (1-minute increments and 1-hour increments)
    Other: Auto-repeat
  • 5 daily alarms (with 1 snooze alarm)
  • Hourly time signal
  • Full auto-calendar (to year 2099)
  • 12/24-hour format
  • Regular timekeeping
    Analog: 2 hands (hour, minute (hand moves every 20 seconds)), 1 dial (speed)
    Digital: Hour, minute, second, pm, month, date, day
  • Accuracy: ±15 seconds per month
  • Approx. battery life: 2 years on CR1220
  • Size of case : 55×51.2×16.9mm
  • Total weight : 70g

GA-100 Comparison Table with similar G-Shock Watches


Price (Amazon)

Year of first Release





±15 seconds per month

±15 seconds per month

±15 seconds per month (with no signal calibration)

SmartWatch Features





LED light (Super illuminator)

LED light

Neobrite (hands and hour markers) and LED light

Case / bezel material



Resin / Aluminum


Mineral Glass

Mineral Glass

Mineral Glass


5 years on CR2016

2 years on CR1220

Solar powered CTL920

Size (mm) *we consider 48.9×42.8×13.4 to be a traditional watch size (as in DW-5600). So you are to compare how far or close the watch is to this size




Full features (if you want to know more)

Recent News about GA-100 

All Casio GA-100 News →

You ask, we answer…

How does Speed measurement in GA-100 work?

If you know the distance, you will know the speed in your watch.

What does ISO 764 class magnetic resistant in GA-100 mean?

A magnetic-resistant plate is mounted on the module. The plate prevents magnetic fields from interfering with proper movement of the hands in daily use.

What model range does GA-100 belong to?

STANDART ANA-DIGI (This Line includes Digital and Analog displays on G-Shocks that are the best in “price/quality” category. Usually have traditional digital functions, but with beautiful hands. Don’t worry, the hands won’t prevent you from seeing digits, since there is a special Hand Shift technology that moves them to the neutral position).

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