The $20 Watch Worn by Terrorists, Presidents, and Osama Bin Laden

The Casio F91W is, at first glance, as harmless as a watch gets. Launched in 1991, it’s a basic black digital timepiece, the kind you find at airport kiosks, petrol stations, and tucked into hipster wrists beside oat milk lattes. But beneath its retro charm lies one of the strangest and darkest reputations in horological history.

This $20 digital watch has been worn by everyone from Barack Obama to Napoleon Dynamite. It’s also been found on the wrists of ISIS operatives, al-Qaeda bombmakers, and, most infamously, Osama bin Laden himself.

During the early 2000s, photographs surfaced showing bin Laden a Casio F91W. While the image sparked curiosity among civilians, intelligence officers saw something else: a potential red flag.

According to declassified documents and first-hand accounts from the field, this watch wasn’t just a coincidence. It was a tool.

The F91W had become known in national security circles as “the terrorist watch,” a term rooted in field evidence. At Guantanamo Bay, over 50 detainees were found wearing either the F91W or its metal cousin, the Casio A159W.

A significant portion of those individuals were reportedly trained in explosives. CIA memos even noted that possession of this watch was considered a marker of possible terrorist training.

It wasn’t just availability that made the F91W the go-to choice for jihadist networks. It was functionality. The watch’s long battery life, reliable digital alarm, and rugged plastic casing made it ideal for timing devices in improvised explosive devices (IEDs).

With the addition of a 9-volt battery, circuit board, and basic wiring, bombmakers could create simple but lethal timed charges.

In 1994, al-Qaeda bomber Ramzi Yousef used an F91W to detonate a device aboard Philippine Airlines Flight 434. The bomb exploded, killing a passenger and proving the watch’s deadly potential.

Years later, Ahmed Ressam, better known as the “Millennium Bomber,” was arrested with four explosives timed with F91Ws as he tried to enter the U.S. His target was LAX. His arrest led to one of the largest terrorism investigations in North American history.

One former intelligence officer, writing under the Watches of Espionage project, recalled a visit to a makeshift prison during a temporary deployment in a conflict zone. Among the “pocket litter” confiscated from an ISIS detainee were two Casio F91W watches. While not definitive evidence of wrongdoing, they were enough to raise suspicion. A CIA targeter on site reportedly remarked, “It’s a common watch used by bomb makers as a detonation timer.”

But it’s never black and white. The officer went on to note that the same watch is also worn by U.S. soldiers, CIA operatives, and even mountain shepherds in Turkey. Like the AK-47 or the Toyota Hilux, the F91W is a ubiquitous tool, durable, cheap, and functional. That’s precisely why it’s become a dual-use symbol: a device that, on the surface, is harmless but can easily be weaponised.

Despite his anti-Western ideology, Osama bin Laden appeared in several propaganda videos wearing branded wristwatches, namely the Casio F91W and a Timex. These were reportedly the only Western consumer products he regularly wore. Some analysts saw this as hypocrisy, others as pragmatism. Either way, it cemented the F91W as part of modern conflict iconography, worn alongside AKS-74Us and long, sand-coloured robes.

It’s no exaggeration to say the watch became a visual marker for Western intelligence agencies. It also became a subject of satire, conspiracy theories, and cult status. The absurdity of a $20 watch being listed in detainment justifications at Guantanamo Bay says as much about the surveillance state as it does about asymmetric warfare.

Today, the F91W remains in production, virtually unchanged. Casio reportedly manufactures up to three million of them a year.

You can buy one for less than the price of a pub lunch, and millions of ordinary people wear them every day.

Some do it for style. Others for nostalgia. And some, perhaps, because when you’re operating in a world where smartphones are GPS trackers and digital silence is survival, a simple wristwatch is the safest tool in your kit.

Like the Rolex Submariner or Omega Speedmaster, the Casio F91W is now a cultural symbol. But unlike those Swiss giants, its legacy is rooted not in luxury or precision, but in contradiction. It is a watch that tells more than just the time. It tells a deadly story from the discount aisle.