Casio’s new G-SHOCK MUDMAN GDG-B100 series pairs a Memory-in-Pixel (MIP) LCD with step counting and basic running and interval-timing tools. It comes in black, dark green and sand; its distance correction uses GPS from a paired phone, rather than onboard GPS navigation.
What is new in the GDG-B100?
Casio positions the GDG-B100 as a MUDMAN in its MASTER OF G line, adding a higher-information MIP display and activity and training features to a rugged digital watch. Casio says the display is designed to stay readable in bright outdoor light, including direct sunlight, and the automatic red LED backlight is intended to help preserve the wearer’s dark adaptation.
![Casio GW-9500-1JF [G-Shock Master of G Series MUDMAN Triple Sensor Model] Watch Japan Import July 2023 Model](https://m.media-amazon.com/images/I/41bbHfxiCdL._SL160_.jpg)
The series retains MUDMAN’s protective design. Casio describes a bumper guard, shock-, dust- and mud-resistant construction, a carbon-fiber-reinforced resin case, and gaskets around button shafts to help keep mud and dust out. These are the manufacturer’s design claims, not a guarantee that a watch is indestructible.
What do the activity and training features do?
An accelerometer counts steps. For timed exercise, the watch adds a stopwatch, interval timer and storage for up to 100 lap times. It can also display distance, speed, pace and estimated calories.
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- Case size (L× W× H): 52 × 46.3 × 16.3 mm
- Shock Resistant, Mud Resistant, 200 meter water resistant, Auto Dual EL Backlights with Afterglow, Low Temperature Resistant, World Time - 29 time zones (48 cities), city code display, daylight saving on/off, 1/100 second stopwatch, Measuring modes: Elapsed time, split time, 1st-2nd place times, 1/100 second stopwatch
- Countdown timer -start time setting range: 1 minute to 24 hours (1-minute increments and 1-hour increments), Auto-repeat, progress beeper, Four Multi-function alarms & 1 snooze alarm, Hourly time signal, Full auto-calendar ,12/24 hour formats, Button operation tone on/off , Flash alert
Distance correction is the key qualification: Casio says the watch can use GPS data from a paired phone to adjust distance measurement. It can retain the adjusted value and continue measuring running distance when no longer connected to the phone. That is not the same as having standalone GPS for route tracking or navigation. The documented feature set is basic activity and training tracking; the official specifications cited here do not establish heart-rate tracking.
What does Bluetooth add?
Bluetooth Smartphone Link connects the watch to Casio’s WATCHES app. Casio lists automatic time adjustment, watch settings, world time for about 300 cities, activity and life-log data, and phone-based GPS distance correction. Supported phone functions include a phone finder and notifications for calls, emails, social posts, calendar notices and reminders. These features depend on a compatible paired phone and the app.
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Which GDG-B100 colors are available?
| Model | Color description |
|---|---|
| GDG-B100-1 | Black; shown on Casio’s official product page |
| GDG-B100-1A3 | Dark green with orange accents; identified by T3’s launch coverage |
| GDG-B100-1A5 | Sand with a black bezel; shown on Casio’s official product page |
How much do the watches cost, and when can you buy them?
T3 reported on October 1, 2026, that each colorway was priced at £200 in the UK, with availability expected in October. That is a UK-reported price, not a confirmed global price or a guarantee of current stock.
In an October 3, 2026 update, Notebookcheck said the three UK listings were showing an “Available soon” or sign-up state rather than an order option, and that US pricing had not been announced. Those reports do not establish whether the watches became orderable after October 3. Check the relevant regional Casio store or an authorized retailer for current stock, seller identity and the correct model code.
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Best Value
- Featuring a Black Band, Black Case, Scratch Resistant Mineral Crystal
- International products have separate terms, are sold from abroad and may differ from local products, including fit, age ratings, and language of product, labeling or instructions
- Original box and packaging: Watch back, but it might be different in the printed image
- Scratch resistant mineral
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- For the fearless adventurer and nature lover, a robust and tireless Master of G MUDMASTER with case and bezel made of durable carbon and environmentally friendly materials.
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- Bio-Based Resin Case and Band, Stainless Steel Case Back
- Mineral Crystal, Multi-Function Digital Function including Digital Compass
- Case Size: 52.7 mm Diameter, 16.9 mm Thickness
- Water Resistant - 200 M
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
