Casio G-SHOCK 2100 Series Neon Analogue Digital Watch (GA-2100-1A3ER)

Overview

The Casio G-SHOCK GA-2100-1A3 combines the iconic octagonal design of the G-SHOCK 2100 Series with a striking black-and-neon-green colour scheme. Featuring a textured matte black case, bezel and strap with vibrant green accents across the dial, this analogue-digital watch delivers a distinctive contemporary appearance while retaining the exceptional durability that has made G-SHOCK a trusted choice for demanding environments.

Built around Casio's advanced Carbon Core Guard structure, the GA-2100-1A3 offers dependable shock resistance in a remarkably lightweight and slim design. Its 200-metre water resistance, dual LED illumination, World Time functionality and comprehensive range of timing features make it equally practical for professional use, outdoor activities and everyday wear. Measuring just 11.8 mm thick and weighing only 51 g, it combines the toughness of G-SHOCK with the comfort of a streamlined everyday watch.

Key Features

• Iconic octagonal G-SHOCK 2100 Series design with a slim, lightweight profile
• Textured matte black resin case, bezel and strap
• Vibrant neon green dial accents for a distinctive, high-contrast appearance
• Phosphorescent hour and minute hands for improved visibility in darkness
• Carbon Core Guard structure for lightweight shock resistance
• 200-metre water resistance for swimming and demanding outdoor conditions
• Analogue-digital display with separate day indicator
• Double LED Super Illuminator for improved visibility in low-light environments
• World Time covering 31 time zones and 48 cities, plus UTC
• 1/100-second stopwatch with elapsed and split-time measurement
• 24-hour countdown timer for training and everyday timing tasks
• Five daily alarms and optional hourly time signal
• Hand Shift function for an unobstructed view of the digital display
• Approximately three-year battery life
• Lightweight 51 g construction with a slim 11.8 mm case

Specifications

• Model: GA-2100-1A3
• UK Model Reference: GA-2100-1A3ER
• Collection: G-SHOCK 2100 Series
• Display: Analogue and digital
• Case Dimensions: 48.5 × 45.4 × 11.8 mm
• Weight: 51 g
• Case & Bezel Material: Carbon / resin
• Case Colour: Matte black
• Accent Colour: Neon green
• Strap: Black resin band
• Compatible Wrist Size: 145–215 mm
• Glass: Mineral glass
• Construction: Shock Resistant, Carbon Core Guard
• Water Resistance: 200 metres (20 bar)
• Power Source: Two SR726W batteries
• Battery Life: Approximately 3 years
• Timekeeping Accuracy: ±15 seconds per month
• Illumination: Double white LED Super Illuminator
• Additional Features: Phosphorescent hands, Hand Shift and full auto calendar

Matte Black Design with Neon Green Accents

The GA-2100-1A3 offers a bold interpretation of the classic G-SHOCK octagonal silhouette, combining understated matte black resin with vibrant neon green detailing. The textured finish gives the case and strap a purposeful, contemporary appearance, while the contrasting colour accents introduce a distinctive visual identity without compromising the watch's practical design.

The dark dial provides a strong backdrop for the neon green details, creating a modern aesthetic that stands apart from conventional monochrome G-SHOCK models. Phosphorescent paint on the hour and minute hands helps maintain analogue time visibility in darkness after exposure to light.

Unlike the translucent GA-2100K models, the GA-2100-1A3 uses a solid matte black finish, making it particularly appealing to users who prefer a more understated watch with a controlled splash of colour. Its familiar octagonal bezel retains the distinctive proportions that have made the 2100 Series one of G-SHOCK's most recognisable collections.

Carbon Core Guard Protection

At the heart of the GA-2100-1A3 is Casio's Carbon Core Guard structure, which uses carbon fibre-reinforced resin to protect the internal watch module against shocks and impacts. This advanced construction combines strength with reduced weight, allowing the watch to maintain its slim proportions without sacrificing the durability expected from G-SHOCK.

The carbon-reinforced case provides dependable protection against the knocks and vibration encountered during everyday activities, while the flexible resin strap offers a secure and comfortable fit. Weighing just 51 g, the GA-2100-1A3 is considerably lighter than many traditional rugged watches, making it comfortable during long working days, travel and physical activity.

With 200-metre water resistance, the watch is suitable for swimming, wet weather and demanding outdoor conditions. Durable mineral glass provides additional protection for the dial, while G-SHOCK's shock-resistant construction helps safeguard the movement during active use.

Analogue-Digital Timekeeping

The GA-2100-1A3 combines traditional analogue timekeeping with the convenience of a multifunction digital display. Two central hands provide hour and minute indications, while a dedicated day indicator and compact digital display allow users to access additional information without compromising the balanced appearance of the dial.

The integrated Hand Shift function temporarily moves the analogue hands away from the digital display when they obstruct important information. This practical feature makes it easier to read stopwatch measurements, countdown settings and other digital functions without waiting for the hands to move naturally.

World Time functionality covers 31 time zones across 48 cities, plus Coordinated Universal Time (UTC), with selectable daylight saving settings. This makes the watch useful for international travel, coordinating activities across different regions and monitoring time differences.

Double LED Super Illuminator

The GA-2100-1A3 features Casio's Double LED Super Illuminator system, providing separate white LED illumination for the analogue dial and digital display. This dual-light arrangement improves visibility in darkness, allowing users to check the time and access digital functions in poorly illuminated environments.

Both illumination systems offer selectable 1.5-second or 3-second lighting durations with afterglow. The phosphorescent hour and minute hands provide additional visibility following exposure to light, helping users read the analogue time without always activating the LEDs.

Whether checking the time during evening activities, working in low-light conditions or travelling after dark, the combination of LED illumination and luminous hands supports dependable time reading throughout the day and night.

Watch Features & Functions

• World Time: 31 time zones covering 48 cities plus Coordinated Universal Time (UTC), with daylight saving on/off settings.
• Stopwatch: 1/100-second measurement for the first 60 minutes, switching to one-second measurement thereafter, with a maximum measuring capacity of 23 hours, 59 minutes and 59 seconds.
• Stopwatch Modes: Elapsed time, split time and first/second-place finish times.
• Countdown Timer: Adjustable from one second to 24 hours, with one-second, one-minute and one-hour setting increments.
• Daily Alarms: Five independent daily alarms for reminders and scheduled activities.
• Hourly Time Signal: Optional audible alert every hour.
• Double LED Light: Separate white LED illumination for the analogue dial and digital display, with selectable 1.5-second or 3-second duration and afterglow.
• Hand Shift: Temporarily moves the analogue hands away from the digital display for improved visibility.
• Full Auto Calendar: Automatically adjusts the date through to 2099.
• Time Format: Selectable 12 or 24-hour digital display.
• Button Tone: Option to enable or disable button operation sounds.
• Analogue Display: Hour and minute hands, with the minute hand advancing every 20 seconds, plus a dedicated day indicator.
• Digital Display: Hours, minutes, seconds, AM/PM, month and date.

Lightweight Durability for Everyday Wear

The GA-2100-1A3 combines the ruggedness of G-SHOCK with a practical, lightweight design that remains comfortable throughout extended periods of wear. Its slim 11.8 mm case sits neatly on the wrist, while the flexible resin strap provides a secure fit without unnecessary bulk.

The combination of Carbon Core Guard protection, 200-metre water resistance and reliable battery-powered operation makes the watch particularly suitable for users who want dependable equipment without frequent charging or complicated maintenance.

Powered by two SR726W batteries, the GA-2100-1A3 delivers approximately three years of operation under normal conditions. Its straightforward analogue-digital interface and comprehensive timing functions make it a versatile choice for work, travel, training and everyday activities.

Why Choose the Casio G-SHOCK GA-2100-1A3?

The GA-2100-1A3 combines the timeless appeal of the G-SHOCK 2100 Series with a distinctive matte black and neon green colour scheme. Its textured resin construction, contrasting dial accents and phosphorescent hands create a practical yet visually striking design that stands apart from conventional black G-SHOCK models.

Beyond its appearance, the watch delivers the proven performance that has made the 2100 Series so popular. Carbon Core Guard construction, 200-metre water resistance, Double LED Super Illuminator technology and comprehensive timekeeping functions provide dependable everyday versatility, while the lightweight 51 g design ensures lasting comfort. For anyone seeking a durable analogue-digital watch that combines understated styling with a distinctive touch of colour, the GA-2100-1A3 is an excellent choice.

Authorised Casio Retailer

TacTree is an authorised Casio UK retailer. All Casio watches supplied are 100% genuine, brand new and sourced through approved UK distribution channels. Orders are supplied with official Casio packaging and manufacturer documentation for complete authenticity and peace of mind.