A timeless G-SHOCK classic reinvented with solar energy, Bluetooth convenience, and next-level durability.

Upgrade the retro look you love with the iconic octagonal GA-2100 line — now supercharged with Smartphone Link and Tough Solar power.
This model keeps the beloved slim profile and design concept of the very first G-SHOCK, but adds modern tech, improved convenience, and stronger materials for everyday performance.

Built with the Carbon Core Guard structure, the watch remains incredibly light, durable, and shock resistant, while still giving you the same comfortable fit that made the GA-2100 series so famous.

The dial has been enhanced using dual-layer construction, adding depth and texture with different surface finishes that elevate the look of the LCD and inset dial. Inspired by the early color releases of G-SHOCK’s legendary DW-5600C, this model also comes in bold retro color options — blue, green, and all-black — for a clean, minimalist style.

With Tough Solar keeping your watch powered and Bluetooth ensuring perfect accuracy, the GA-B2100 line delivers everything you love — now on an entirely new level.

⭐ Major Highlights

• 🟩 Retro octagonal design inspired by the original G-SHOCK

• 🔋 Tough Solar power (no battery changes)

• 📱 Smartphone Link (Bluetooth) for precise time and easy settings

• 💪 Shock-resistant Carbon Core Guard structure

• 💧 200-meter water resistance

• 🌍 World time for 38 cities

• 🌙 Super Illuminator double LED light

• 🔔 5 alarms + reminders via app

• 📍 Time & Place log + Phone finder

• 🕒 Slim profile and lightweight comfort

⭐ Detailed Specifications

🔹 Basic Information

• Case size: 48.5 × 45.4 × 11.9 mm

• Weight: 52 g

• Case & bezel material: Carbon / Resin

• Band: Resin band

• Construction: Shock Resistant, Carbon Core Guard

• Water resistance: 200 m

🔹 Time Adjustment

• Bluetooth®: Automatically adjusts time when connected to your smartphone

🔹 Power Supply

• Tough Solar (solar powered)

🔹 Smartphone Link (CASIO WATCHES App)

• Automatic time adjustment (4× per day)

• Simple watch setting

• 300+ world time cities

• Phone finder

• Time & Place log

• Reminders (up to 5)

• Home/World time switching

• Alarm & timer settings

🔹 Exterior

• Glass: Mineral Glass

• Neobrite: Hands glow in the dark

⭐ Watch Features

🌍 World Time

• 38 time zones

• City name & code display

• DST on/off

• Auto summer time

• Swap home & world city

🏁 Stopwatch

• 1/100-second stopwatch

• Measuring capacity:

  • Up to 60 min with 1/100-sec accuracy

  • After 60 min: up to 23:59’59

• Modes: Elapsed, lap/split time

⏱️ Countdown Timer

• Unit: 1 second

• Range: up to 60 minutes

🔔 Alarms

• 5 daily alarms

• Hourly time signal

💡 Lighting

• Double LED (Super Illuminator)

• Selectable duration: 1.5s or 3s

• LED color: White

📅 Calendar & Settings

• Auto-calendar to 2099

• Button tone on/off

• Power Saving mode

• Battery level indicator

🔋 Battery Performance

• 7 months on rechargeable battery (normal use, no light)

• 18 months in total darkness (power save on)

🕒 Regular Timekeeping

Analog:

• Hour & minute hands (hand moves every 20 seconds)

• Inset dial for battery level/mode

Digital:

• Hour, minute, second

• AM/PM

• Month, date, day

⭐ Extra Features

• Hand shift function

• 12/24-hour format

• Date/month swap

• Day name displayed in 6 languages