The Casio G-SHOCK GA-2100HDS-7A1 is the white-and-blue analog-digital watch in the Hidden Glow Vol. 2 collection. Its blue phosphorescent dial details are designed to glow in darkness, while separate LEDs illuminate the analog face and digital display. Casio’s published specifications describe a 48.5 × 45.4 × 11.8 mm, 51 g watch with shock resistance, 20-bar water resistance and the familiar GA-2100 layout. The details below are manufacturer-published; this is not a firsthand wear or performance test.
Which Hidden Glow watch is the GA-2100HDS-7A1?
GA-2100HDS-7A1 is the exact model code for the watch covered here. Casio’s US collection page distinguishes it as an online-exclusive option and also lists the related GA-2100HDS-7A. The suffix matters: these are distinct catalog entries, so check the complete code when identifying the watch. Casio’s international collection page presents the lineup as G-SHOCK watches with blue phosphorescent faces inspired by the ocean at night. Casio US exact-model page · Casio International exact-model page
The collection also includes different watch designs such as the DW-6900HDS, GA-110HDS and GA-700HDS. They are not simply alternate names for this GA-2100: their cases, displays and listed functions differ.
What glows—and what the LEDs do
Casio describes the white-and-blue color scheme as evoking a summer sea, with the blue phosphorescent face inspired by bioluminescent plankton. That imagery is brand design language; the glow comes from phosphorescent material in the dial, not actual plankton or an electronic screen. Depending on the model, Casio says this material appears across the whole dial or in selected areas and emits a gentle blue glow in darkness. Casio Hidden Glow Vol. 2 collection page
#1 Best Overall
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- The rugged watch's 45.4mm case is expertly crafted from fine resin mixed with carbon fiber, an innovative composition that is lighter and more durable than resin
- The smooth black dial features an analog-digital display and double LED light feature, for easy visibility in the dark
The GA-2100HDS also has a separate double-LED system: one LED illuminates the analog face and another lights the digital display. Casio calls this Super Illuminator. The phosphorescent material and LEDs serve different purposes—the former glows in darkness, while the LEDs provide active illumination when switched on. The model page lists selectable 1.5- or 3-second illumination and an afterglow. It does not provide a measured glow duration for the phosphorescent material.
GA-2100HDS-7A1 specifications
| Specification | Casio-listed detail |
|---|---|
| Case dimensions | 48.5 × 45.4 × 11.8 mm |
| Weight | 51 g |
| Construction | Shock resistant; Carbon Core Guard structure |
| Case and bezel | Carbon/bio-based resin |
| Band | Bio-based resin |
| Water resistance | 20 bar / 200 meters, as rated by Casio |
| Power | Two SR726W batteries; approximately three years’ battery life, per Casio |
| Accuracy | ±15 seconds per month, per Casio |
| Time display | Analog hour and minute hands and a day dial, plus digital hour, minute, second, PM, month and date |
These are manufacturer specifications, not independently measured results. A 200-meter rating is not a guarantee for every kind of water activity; follow Casio’s usage and care guidance for the watch.
Rank #2
Timekeeping and everyday functions
In addition to its analog hands and digital display, the GA-2100HDS-7A1 lists these functions:
- World time: 31 time zones covering 48 cities plus UTC, with daylight-saving time on/off.
- Stopwatch: 1/100-second measurement for the first 60 minutes, then one-second measurement; elapsed, split, and first- and second-place time modes.
- Countdown timer: one-second measurement unit, with a maximum setting of 24 hours.
- Alarms: five daily alarms and an hourly time signal.
- Hand shift: moves the hands aside to make digital information easier to view.
- Other settings: 12/24-hour format and a full auto-calendar through 2099.
Casio’s international product page gives the approximate three-year battery estimate for two SR726W batteries. Actual battery life can vary with use, including how often the lights and other functions are used; no independent battery-life test is represented here. Casio International GA-2100HDS-7A1 specifications
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Rank #3
Bio-based resin: what Casio says
Casio identifies bio-based resin in key bezel and band components; the exact-model specification lists a carbon/bio-based resin case and bezel and a bio-based resin band. Casio says this material choice is expected to help reduce environmental impact, but the cited product information does not quantify a footprint reduction or provide a lifecycle comparison. The material description alone therefore does not establish a specific environmental benefit for this watch.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Release and regional availability
Availability and pricing depend on region and date. Casio G-SHOCK Singapore announced on 3 June 2025 that the collection would be available online and in stores from 6 June 2025 at 11:00 a.m. Singapore local time. That announcement describes a Singapore release, not a worldwide launch schedule. Casio Singapore Hidden Glow Vol. 2 announcement
Rank #4
- Case
- - Case Material: Resine
- - Case Shape: Round
- - Case Colour: Black
- - Crystal: Mineral crystal
For Japan, Casio lists the regional GA-2100HDS-7A1JF as discontinued, with a June 2025 release month and a suggested retail price of ¥18,700 including tax. This is a Japan-market historical price and status; it does not establish current stock or the present price or discontinuation status in the US or elsewhere. Casio Japan GA-2100HDS-7A1JF page
Quick Recap
Best Value
- Classic and charming watch perfect for every occasion -The watch has a calendar function: Day-Date, Stop Watch, Worldtime, Countdown, Alarm, Light
- Crystal: Plastic
- Crystal: Mineral
- Strap:Plastic Black
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.
