Casio G-Shock GST-B400 Watches

Important Information

  • Price — may be available 
    *average Amazon Price, we may earn commission from purchases
  • Year of first Release —  2021
  • Module Number — 5657 / Manual
  • Model Range — G-STEEL (G-Steel are refined watches and combine high-quality materials with G-Shock’s standard of toughness. Its layered guard structure boasts a double-layer bezel construction of stainless steel and resin or resin and fine resin which delivers the hard, sleek beauty of metal while retaining the impact absorption of resin.)
  • Other Divisions the GST-B400 belongs to: *you may find all watches of the division by clicking on the link
  • Battery Type — Solar (G-Shock Batteries)

GST-B400 Model Range *may be updated


The most distinctive specs of GST-B400 *Editorial
The Slimmest-Ever G-STEEL as for 2021 (it features a new, improved module built to deliver slimness)
Beautiful battery level indicator at 9 o’clock (displays the mode, battery level and more)
Vapor deposition-treated dials (for highly chromogenic and distinctive coloration)
Tough Solar (CASIO’s original solar-charging system converts not only sunlight but also light from fluorescent lamps and other sources into power)
G-SHOCK Connected App (you may manage all watch settings through your phone)


Official GST-B400 Video

Official Marketing Focus from Casio

Introducing new color variations to the lineup of slim G-STEEL GST-B400 models with new, improved designs made possible by a thin module and carbon core guard structure. There is a standard model in this lineup, the GST-B400 with silver color face and resin band.
The GST-B400 is made possible by even further miniaturization of its parts and thinning of its modules without sacrificing any Bluetooth or solar function.Power consumption has also been significantly reduced.

Official GST-B400 Specs / Features *for base version GST-B400-1A

  • Case / bezel material: Resin / Stainless steel
  • Resin Band
  • Mineral Glass
  • Neobrite
  • Shock Resistant
  • Carbon Core Guard structure
  • 200-meter water resistance
  • Shock resistant (G-SHOCK)
  • Tough Solar (Solar powered)
  • Double LED light
    LED light for the face (Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow)
    LED backlight for the digital display (Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds),afterglow)
  • Mobile link (Wireless linking using Bluetooth®)
  • Hand shift feature (Hands move out of the way to provide an unobstructed view of digital display contents)
  • World time
    38 time zones (38 cities + coordinated universal time), city code display, city name display, daylight saving on/off, auto summer time (DST) switching, Home city/World time city swapping
  • 1/100-second stopwatch
    Measuring capacity: 00’00”00~59’59”99 (for the first 60 minutes)
    1:00’00~23:59’59 (after 60 minutes)
    Measuring unit: 1/100 second (for the first 60 minutes)
    1 second (after 60 minutes)
    Measuring modes: Elapsed time, lap/split time
  • Countdown timer
    Measuring unit: 1 second
    Countdown range: 60 minutes
    Countdown start time setting range: 1 second to 60 minutes (1-second increments and 1-minute increments)
  • 5 daily alarms
  • Hourly time signal
  • Battery level indicator
  • Power Saving (display goes blank to save power when the watch is left in the dark)
  • Full auto-calendar (to year 2099)
  • 12/24-hour format
  • Button operation tone on/off
  • Date/month display swapping
  • Day display (days of the week selectable in six languages)
  • Regular timekeeping
    Analog: 2 hands (Hour, minute (hand moves every 20 seconds))
    1 dial (battery level, mode)
    Digital: Hour, minute, second, pm, month, date, day
  • Accuracy: ±15 seconds per month (with no mobile link function)
  • Approx. battery operating time:
    7 months on rechargeable battery (operation period with normal use without exposure to light after charge)
    18 months on rechargeable battery (operation period when stored in total darkness with the power save function on after full charge)
  • Size of case : 46.6×49.6×12.9mm
  • Total weight : 80g

Recent News about GST-B400 

All Casio GST-B400 News →


You ask, we answer…

How does Tough Solar in GST-B400 work?

It’s CASIO’s original solar-charging system that converts not only sunlight but also light from fluorescent lamps and other sources into power.

What are Vapor deposition-treated dials in GST-B400?

They are used for highly chromogenic and distinctive coloration.

What does G-SHOCK Connected App in GST-B400 do?

You may manage all watch settings through your phone.