Casio's New G-Shock Mudmaster Arrives Outside Japan With a Magma Look and Biomass Build
Casio has launched the G-Shock Mudmaster GWG-B1000MG-1A9 in the US at $900, marking the first availability of the model outside Japan. A UK listing at £800 is already live but marked "coming soon," per G-Central. For anyone considering a serious outdoor or tactical watch, this sits at the top end of a crowded field — and a few details set it apart.
The look
The design takes cues from volcanic imagery, with Casio calling the colorway "Magma Gold." The bezel is forged metal with a multi-tone gold ion plating (IP), while the hands and indices get red and orange accents. The strap uses a technique called garal color molding — different colored resins are blended to produce a layered, marble-like pattern. It reads as bold rather than flashy in person.
The case is built from Carbon Core Guard resin combined with bio-based plastic, keeping weight at 114g — light for a watch this substantial. The dial sits behind sapphire crystal with anti-reflective coating, and water resistance is rated to 200 meters (20 bar).
The GWG-B1000MG-1A9 features a forged metal bezel with multi-tone gold ion plating and a garal-molded resin strap.
The sensors
Triple Sensor is the core hardware sell here: digital compass, altimeter/barometer, and thermometer — all in one package. Multi-Band 6 radio sync automatically calibrates the time against signals from six atomic clock towers worldwide, so manual time-setting is rarely needed.
Triple Sensor packs a digital compass, altimeter/barometer, and thermometer into the Mudmaster case.
The smart features
Bluetooth connects the watch to iOS and Android via the Casio Watches app. Three functions stand out: automatic time correction, mission log tracking (a GPS movement journal), and Location Indicator — a physical watch hand at the 3 o'clock position that points toward a waypoint you've set in the app. That last feature is genuinely useful in low-visibility conditions where staring at a phone screen isn't practical.
Power comes from Tough Solar charging. With normal use and no light source, the battery lasts around six months; in full power-save mode in complete darkness, Casio claims up to 24 months, as confirmed by Gizmochina.
Worth £800?
At this price, the Mudmaster competes against the Apple Watch Ultra (fitness-focused, ~£799), Garmin Epix Gen 2 (strong outdoor sensors, around £700), and TAG Heuer Connected at the luxury end. The Casio's case is its sensor suite, solar charging with no need for daily plug-ins, and a build rated for genuinely harsh conditions — not just weekend hiking. If a smartwatch's short battery life has ever frustrated you in the field, this is a direct answer to that problem.
