The Casio G-Shock: From a Broken Father's Watch to the Wrist of Every Navy SEAL

If you spend any time around military personnel, firefighters, divers, astronauts, or just people who break things for a living, you will notice the same square black digital watch showing up again and again. It is not a Rolex. It is not a Garmin. It is a Casio G-Shock, and over the last 42 years it has quietly become the most successful tool watch in history, with over 140 million units sold since 1983 and a reputation for surviving things that destroy every other watch on the market.

The G-Shock was not designed for the military. It was designed because one man in Tokyo was upset that he dropped his father’s watch on the pavement and broke it. The fact that it ended up on the wrists of Navy SEALs, British Army captains, NASA astronauts, and the most lethal sniper in U.S. military history is a story about what happens when an engineer takes durability seriously enough to throw 200 prototypes out of a bathroom window.

This article is a look at where the G-Shock came from, the “Triple 10” philosophy that defined it, how it became the default watch of the modern military, the specific models that earned NATO Stock Numbers and Ministry of Defence contracts, its cameo in pop culture, and where the brand sits in 2025.

The Origin: A Broken Watch and a Bouncy Ball

The G-Shock exists because of a small accident in 1981. Kikuo Ibe, a young engineer at Casio Computer in Tokyo, was walking down the street when he bumped into a pedestrian. The collision was hard enough to snap the strap of the mechanical wristwatch his father had given him, and the watch hit the pavement and shattered beyond repair, caseback and hands popping off on impact. Ibe was devastated. He later refused to disclose the manufacturer, saying only that it was a Japanese made three hander with a calendar complication.

Out of that loss came an obsession. Ibe submitted a proposal at Casio for a single straightforward concept: build a watch that could survive being dropped. He formed an eight person unit, half jokingly dubbed “Project Team Tough,” and set himself a target he called the “Triple 10”:

Survive a 10 meter free fall onto a hard surface.
10 bar water resistance (later upgraded to 20 bar / 200 meter).
10 year battery life.

The number 10 was chosen because Ibe’s office was on the second floor, roughly 10 meters above the ground, and that height became the benchmark for the drop test. He famously tested early prototypes by throwing them out of the bathroom window at the Casio factory. He threw more than 200 prototypes out of that window. Every one of them broke.

The breakthrough came, as breakthroughs often do, from an unrelated observation. Ibe was watching a girl playing with a bouncy rubber ball in a park and noticed that the centre of the ball did not seem to suffer the shock of the ball hitting the ground. The outside absorbed the impact; the inside stayed still. He realised the same idea could protect a watch movement: suspend the delicate quartz module inside a hollow case, supported at only a few points by shock absorbing buffers, so that the case took the impact and the module “floated.” That hollow, floating module construction remains the fundamental structure of every G-Shock today.

After two years and those 200 broken prototypes, the first G-Shock, the DW-5000C-1A, went on sale in April 1983. It delivered 20 bar water resistance (better than the 10 bar target), ISO and JIS certified shock resistance, and a 7 year battery life (slightly under the 10 year target). It cost roughly $50 in 1983 dollars. It did not sell well at first. The watch industry was busy competing on slimness, and a chunky 13mm thick resin square looked like a brick on the wrist. Casio almost killed the line.

What saved it was the United States. American skateboarders, surfers, and BMX riders picked up on the G-Shock because it survived the exact abuse they dished out, and from there it crossed into hip hop and street culture. By the early 1990s the G-Shock was a fashion object as well as a tool, and Casio leaned into it with hundreds of colourways, collaborations, and limited editions.

The “Triple 10” and the Hollow Module

The Triple 10 is worth understanding because it is still the design brief for every G-Shock. The five stage shock absorbing system Ibe’s team developed works like this:

A urethane bezel that takes the first impact.
A mineral glass crystal mounted to flex slightly rather than crack.
Stainless steel button guards that protect the pushers from direct hits.
A suspended, floating module held inside the case at only a few points by shock buffers.
The hollow case structure itself, which deforms and rebounds instead of transmitting shock to the movement.

The result is a watch you can drive over with a truck, drop down a flight of concrete stairs, freeze in a block of ice, or leave in the sun, and it will keep ticking. Casio’s marketing eventually settled on the slogan “Unbreakable”, and unlike most marketing slogans, this one is more or less true. The lifetime of a G-Shock is generally limited by the resin case and strap, which degrade after 10 to 20 years of UV exposure, not by the movement inside.

How the G-Shock Conquered the Military

The G-Shock was never designed for soldiers. It was designed for construction workers and anyone else who could not wear a delicate watch to work. But the same properties that made it survive a skatepark made it survive a war zone, and by the late 1980s U.S. service members were buying G-Shocks at Post Exchanges (PXs) with their own money because the issue watches could not keep up.

The shift became irreversible during the Global War on Terror. As the Watches of Espionage project documented, the two decades after September 11, 2001 saw the G-Shock replace the Rolex and Tudor Submariner as the default special operations watch. The reasons were bluntly practical:

A Submariner cost thousands of dollars and required factory servicing. A DW-6600 cost about $50, ran for years on a coin cell battery, and required no maintenance at all.
A Submariner was a lootable object. A dead soldier’s Rolex on an Iraqi insurgent’s wrist was a propaganda problem. A G-Shock was not.
A Submariner could be smashed on a doorframe during a breach. A G-Shock bounced.
A Submariner attracted attention off duty. A G-Shock was invisible.

As one U.S. Navy SEAL put it to Task and Purpose: “The Casio G-Shock is the Toyota Hilux or AK-47 of tactical watches. It’s simple, it’s practical, and it keeps ticking in a sandstorm or after being submerged in mud or water.”

The Four G-Shocks With NATO Stock Numbers

While dozens of G-Shock models have been bought in small unit purchases by militaries around the world, only four have been formally assigned a NATO Stock Number (NSN), the 13 digit code that identifies an item as officially stocked and issued across the NATO supply system. They are:

DW-5600E-1V — the classic square, the same basic shape as the 1983 original.
DW-6600-1V — the model most associated with Navy SEALs in the 1990s and 2000s, with a large front light button designed to be pressed with gloves on.
DW-6900-1V — the successor to the DW-6600, currently the most commonly seen G-Shock on active duty SEALs, including on the wrist of Captain Stephen M. Healey at his July 2025 change of command ceremony at Naval Special Warfare Group 11.
DW-9052-1V — until at least 2018, this was the watch issued to new Navy divers at the Naval Diving and Salvage Training Center and to SEAL candidates at BUD/S training. Photos from 2025 show SEALs still wearing it during dive operations off Key Largo and Key West.

The DW-6600 deserves a special mention. It was the watch Chris Kyle, the deadliest sniper in U.S. military history, wore across his four tours in Iraq with SEAL Team 3, Task Unit Bruiser, between 2003 and 2009. In his autobiography American Sniper, Kyle wrote it plainly: “On my wrist, I’d wear a G-Shock watch. The black watch and its rubber wristband have replaced Rolex Submariners as standard SEAL equipment.” He recorded 160 confirmed kills, the highest total in U.S. military history, with that $50 watch on his wrist. Iraqi insurgents knew him as “The Devil of Ramadi.” The watch was not a personal choice. It was professional standard issue for the men around him.

The UK Ministry of Defence Partnership

The British took a more formal route. In February 2020, Casio G-Shock announced a partnership with the United Kingdom Ministry of Defence to become an official watch supplier to the British Armed Forces. The first release was the British Army x G-Shock Mudmaster GG-B100BA-1A, a limited edition built on the Mudmaster platform with:

A Carbon Core Guard structure and triple layered carbon insert bezel for durability at low weight (92g).
Mud and dust resistant button construction, designed so that soil, debris, and rubble cannot jam the pushers.
A camouflage dial inspired by the British Army’s own Multi Terrain Pattern (MTP).
An all black, low reflection dial, specifically requested by the Army so the watch does not attract attention from hostile surveillance on operations.
A Quad Sensor suite: altimeter barometer, thermometer, compass, and step counter, plus Bluetooth mobile link and a calorimeter.

The British Army Mudmaster retailed at $460 / £399 and was the first of three planned Armed Forces editions. The Royal Air Force x G-Shock Gravitymaster GR-B200RAF-8A followed, and a Royal Navy x G-Shock Frogman GWF-A1000RN-8A completed the set.

Separately, a Freedom of Information response from the UK’s Defence Equipment and Support agency in May 2020 confirmed that the watch formally issued to Royal Navy divers was the Casio G-Shock GAW-100B-1AER, with 135 units issued, replacing the earlier GR-8900-1ER (508 units issued), which had itself replaced the Citizen Promaster Diver BN0000-04H. In other words, the Royal Navy’s working divers are now issued a G-Shock, not a CWC SBS diver.

Prince Harry Wore a $60 G-Shock to War

One of the more striking G-Shock military stories involves Prince Harry. He joined the British Army in 2005 and served for ten years, reaching the rank of Captain. He deployed to Helmand Province, Afghanistan twice: first in late 2007 as a Forward Air Controller calling in air strikes on Taliban positions from the ground (withdrawn after ten weeks when a media breach broke the news blackout), and again in 2012 as an Apache AH-64 helicopter co-pilot gunner, completing 25 sorties.

On his wrist through both deployments was a Casio G-Shock G100-1BV, an ana-digi model with anti magnetic construction (marked “ANTIMAG.I” on the dial), 200m water resistance, and a retail price of roughly $50 to $80. The anti magnetic rating mattered: the Apache cockpit generates significant electromagnetic fields, and a magnetised watch on a pilot’s wrist is a problem. The British royal family is associated with Rolex, Cartier, and Patek Philippe. Prince Harry wore a $60 G-Shock to war, not because he had no other options, but because it was what the job required. He documents the deployments in his 2023 memoir Spare.

The Mudmaster and the Master of G Line

The Mudmaster is part of Casio’s Master of G series, a line of G-Shocks built for specific professional environments. The major families are:

Mudmaster (land, mud and dust resistant) — descended from the 1990s Mudman, with the modern GG-B100 and GWG-1000 series featuring mud resistant cylindrical button shafts and Triple G Resist (shock, vibration, and centrifugal force resistance).
Gulfmaster (sea, barometer and tide graph) — for naval and maritime use.
Gravitymaster (air, aviation oriented) — for pilots, including the RAF collaboration.
Frogman (dive, ISO certified 200m diver’s watch) — the only G-Shock line officially rated for scuba diving, and the basis of the Royal Navy collaboration.
Rangeman (land, Triple Sensor with altimeter, barometer, compass, thermometer) — introduced 2013, the first G-Shock with the full Triple Sensor suite.
Riseman (pressure sensor, predecessor to the Rangeman) — dating back to 1997.

The Mudmaster in particular has become one of G-Shock’s most successful lines, and the British Army collaboration did a lot to move G-Shock from “cheap digital beater” to “serious professional tool watch” in the public mind.

The G-Shock in Space: NASA’s Favourite Digital Watch

The military is only half the story. The G-Shock also made it into orbit. The DW-5600 was officially certified by NASA for space flight, joining a very short list of wristwatches the agency has qualified for astronaut use (the Omega Speedmaster Professional being the most famous, for EVA spacewalk use). Space certified G-Shock models have included the DW-5600C, DW-5600E, DW-5900, DW-6900, and G-9000 Mudman.

The DW-5600 was a popular watch with astronauts during the Space Shuttle era because it was shock resistant, vibration resistant, water resistant, quartz accurate, and ran for years on a single battery. Its stopwatch and countdown timer were genuinely useful for timing mission events and running experiments, and the digital display could show multiple time zones simultaneously (local time in Houston and mission elapsed time, for example). Astronaut John Creighton wore a DW-5600 on STS-36 in 1990, and Bill Nelson wore one on STS-61C. The Smithsonian’s National Air and Space Museum has a flown G-Shock on display in its “Moving Beyond Earth” exhibition, where NASA describes it simply as “crew preferred.”

There is one limit. The G-Shock is qualified for intra vehicular activity (IVA), use inside the spacecraft, but not for extra vehicular activity (EVA), spacewalks. The liquid crystal display freezes in the extreme cold of vacuum, and the watch is not rated for the temperature swings of direct sunlight to shadow in orbit. Kikuo Ibe has said in interviews that an EVA approved G-Shock remains one of his ambitions.

In 2020, Casio released the DW5600NASA20-7CR, a limited edition with the NASA “worm” logo on the dial, “National Aeronautics and Space Administration” printed on the strap, an American flag on the band loop, an engraving of the Moon on the caseback, and an EL backlight that displays an image of the Moon when lit. It came in packaging resembling a Saturn V rocket section. It sold out almost immediately and was limited to one per household.

The G-Shock in Pop Culture

The G-Shock’s military and space credentials are real, but its cultural reach is just as important to the brand. A few highlights:

Speed (1994): Keanu Reeves, as LAPD SWAT officer Jack Traven, wears a G-Shock DW-5600C-1V throughout the film. It is one of the most prominent watch placements in movie history, and the watch community has called the DW-5600C the “Speed G-Shock” ever since. The DW-5600C-1V was a 1987 model, the last of the 5000/5600 line with a screw back case, which makes it a sought after collectible today (clean examples trade at $300 to $500). Reportedly, the watch was not a supplied prop but owned by Keanu Reeves himself.
Breaking Bad: Steven Gomez (Steven Michael Quezada), the DEA agent, wears a G-Shock DW-6400B-1, one of the most shock resistant G-Shocks ever built, with massive side bumpers designed to absorb almost any impact. A DEA agent in the most indestructible G-Shock money can buy, on a show about people who break things.
The Matrix Resurrections (2021): A new look Neo prompted a wave of nostalgia for Keanu Reeves’ 1990s G-Shock era.
A24’s Warfare (2025): G-Shock watches appear on the wrists of the cast, continuing the brand’s run in modern war films.
Hundreds of collaborations with Supreme, A Bathing Ape (BAPE), Palace, NASA, Harley Davidson, John Mayer, NIGO, and Kikuo Ibe’s own 35th anniversary collection, many of which trade well above retail on the secondary market.

The base model black resin DW-5600-1V, however, remains one of horology’s most democratic objects. It costs about $50 new, functions identically whether you pay $50 or $300 for a clean vintage example, and is worn by everyone from Navy SEALs to schoolchildren to astronauts.

G-Shock Today: 140 Million Watches and Counting

As of 2025, Casio has sold over 140 million G-Shocks worldwide since 1983, across more than 100 countries. The line has expanded into several distinct families:

The classic square (DW-5600, GW-M5610, GW-5000): the original 1983 silhouette, now available with Tough Solar charging, Multi Band 6 radio time sync, and in premium made in Japan versions with screw back cases and DLC coated steel.
The full digital round (DW-6900, DW-9052): the SEAL favourites, with the large front light button.
The Master of G series (Mudmaster, Gulfmaster, Gravitymaster, Frogman, Rangeman): the professional tool watches, with sensor suites, mud resistance, and ISO diver certification on the Frogman.
The ana-digi line (GA-100, GA-2100 “Casioak”): analog hands over a digital display, the GA-2100 nicknamed the “Casioak” for its Royal Oak like octagonal bezel, and one of Casio’s biggest sellers of the 2020s.
The MR-G and MT-G premium lines: high end G-Shocks with titanium cases, sapphire crystals, and prices from $500 to $3,000 plus, aimed at the luxury watch market without sacrificing the Tough Solar and radio sync core.

The brand’s strategy in 2025 is to straddle every price point. A recruit can buy a DW-5600 for $50 at the PX. A collector can buy a limited NASA edition for $130. A British Army officer can buy a Mudmaster collaboration for $460. A watch enthusiast can buy a titanium MR-G for $2,500. All of them share the same hollow module DNA that Kikuo Ibe sketched after watching a girl bounce a rubber ball in a Tokyo park in 1981.

Kikuo Ibe himself is still at Casio, in his 70s, as research and development chief engineer. He has said his remaining ambitions are an EVA approved G-Shock for spacewalks and a G-Shock that can survive extreme cold. Given that he threw 200 prototypes out of a bathroom window to get the first one right, nobody is betting against him.

Why a G-Shock Belongs in an EDC Kit

For the ham radio, bushcraft, and everyday carry crowd, the case for a G-Shock is the same one the SEALs make:

Indestructible in normal use. Drop it, smash it, freeze it, submerge it, drive over it. It keeps ticking.
Long battery life. A basic DW-5600 runs 5 to 10 years on a single CR2016 coin cell. The Tough Solar models run indefinitely on any light.
Radio time sync. Multi Band 6 models sync to atomic clock transmitters in Japan, the U.S., the U.K., Germany, and China, and are accurate to within one second to the official time standard, with no user intervention.
Useful functions. Stopwatch, countdown timer, multiple alarms, world time, and on the Master of G models, altimeter, barometer, compass, and thermometer. For field operations, the countdown timer alone is worth the price.
Cheap enough to lose. A $50 G-Shock is not a disaster to lose or break in the field. A $10,000 mechanical watch is.
Invisible. It does not announce you as a person with expensive gear, which in some travel and field contexts is a feature, not a bug.

The honest downside is the resin decay problem. The urethane case and strap of a G-Shock will eventually harden, crack, or crumble after 10 to 20 years of UV and ozone exposure, and the module inside will outlast the case. Casio does not always keep replacement parts in stock for older models, so a 20 year old G-Shock may need a third party resin replacement or a full case swap. The movement, almost always, is still fine.

The other downside is that, unlike a mechanical watch, a G-Shock is disposable by design. When the resin goes and the parts are gone, you buy a new one. There is no heirloom G-Shock in the way there is an heirloom Submariner. But at $50 a pop, that is a trade most working professionals are happy to make.

Closing Thoughts

The G-Shock is the watch industry’s answer to the AK 47 and the Toyota Hilux: not beautiful, not refined, not heirloom, but so good at its one job that it has become the global default. It started as one engineer’s guilt over a broken father’s watch, became a Tokyo playground insight about a bouncing rubber ball, survived 200 prototypes thrown out of a bathroom window, and ended up on the wrists of Navy SEALs, British Army captains, NASA astronauts, and the deadliest sniper in U.S. military history.

Not many $50 objects can claim that. And the next time you see a square black digital watch on someone’s wrist in a photo from a war zone, a fireground, or a space station, you will know exactly what it is, and exactly why it is there. It is there because it does not break.