The thinnest mechanical watches ever made

Buffy Acacia

Thinness has always been prized in the watch world because it serves so many purposes. There’s the welcome practicality of a thin watch being easy to wear, whether it’s supposed to slip into a pocket or under a dress cuff. There’s the aesthetic appreciation of thinness, embodying sophistication and elegance. Finally, there’s the chance to show off a brand’s technical prowess, and that’s what we’ll be focusing on here. The battle for the world’s thinnest watch has created a heated rivalry in the last couple of years, and we’re constantly seeing records broken by brands you’d expect to break them, as well as complete surprises. Until the record is broken again, here are the thinnest mechanical watches ever made.

Piaget Altiplano Ultimate Concept – 2mm

When the Piaget Altiplano Ultimate Concept was released in 2018, it was the world’s thinnest watch. That’s pretty much true for almost every watch in this list, but just because it’s now been beaten four times, that doesn’t make it irrelevant – just one of the thinnest mechanical watches in the world rather than the thinnest. One of the most interesting things about the Piaget AUC is its customizability, with many aspects of the watch available in any colour you wish. Not only that but because it’s been a standard production model since 2020, it can safely be considered a wearable watch with a proven track record of reliability. It has 40 hours of power reserve and requires a specialised tool for winding and setting due to the lack of a crown. Price: CHF 410,000 (~US$481,500)

Piaget Altiplano Ultimate Concept Tourbillon – 2mm

Unlike its non-tourbillon predecessor, the Piaget Altiplano Ultimate Concept Tourbillon, released earlier in the year, is currently a record holder. It’s the world’s thinnest tourbillon watch, which is an important distinction because it thrashes the previous record holder (Bulgari Octo Finissimo Tourbillon), which was 3.95mm thick. To have a 2mm watch both with and without a tourbillon proves Piaget’s expertise in micro-engineering and will likely kickstart a new genre of thinness wars with high complications. How long until we see a <5mm minute repeater or perpetual calendar? To support the 41.5mm case of the Piaget AUC Tourbillon, it’s made out of a surgical-grade cobalt alloy. Price: CHF 600,000 (~US$704,600)

Bulgari Octo Finissimo Ultra – 1.8mm

Nobody outdoes themselves like Bulgari, and while *spoiler alert* the 1.8mm-thick Bulgari Octo Finissimo Ultra has been updated in both specification and thinness, the 2022 version is still worth gawking at. In addition to being jaw-droopingly thin, it also created a surprising amount of discourse around the use of QR codes in watchmaking and the momentary embrace of NFT culture. As a limited edition of just ten pieces, you’ll be unlikely to ever see one in the sandblasted titanium metal. However it will surely remain in lists such as these for years, if not decades, to come. Price: US$440,020

Richard Mille RM UP-01 – 1.75mm

Richard Mille has never been a brand to shy away from extremes, but that didn’t stop the controversial watchmaker from teaming up with one of the most beloved names in the automotive world for its record-breaking achievement. With the Prancing Horse of Ferrari depicted right there on the front of the case, the Richard Mille RM UP-01 looks more like a genuine piece of sci-fi kit than a traditional wristwatch. Beating the previous record by just 0.05mm, several components have been splayed across the case in order to keep it functional. The miniature dial in the middle does tell the time, and star-shaped holes on the left side allow you to wind the watch’s 45-hour power reserve and set the time. Price: US$1,750,000

Bulgari Octo Finissimo Ultra COSC – 1.7mm

Reclaiming the crown at Watches and Wonders 2024, it was clear that Bulgari had set to work slimming down the OF Ultra as soon as it had been announced. Not only did the Swiss-Roman house cut down 0.1mm, but it also managed to get the movement COSC-certified as a chronometer. Because of that, there can be no doubt as to its practicality, but the likelihood of someone wearing this as their daily watch is probably pretty low. It’s cased in solid platinum or titanium (admittedly, not very much of it due to the case’s size) and also features the contentious QR code on the mainspring barrel. Price: US$529,000 (titanium) / US$546,000 (platinum)

Konstantin Chaykin ThinKing – 1.65mm

The jury is still out on whether the Konstantin Chaykin ThinKing is the pinnacle of the world’s thinnest mechanical watches because it has technically only been revealed as a prototype. At 1.65mm thick, it is technically a complete watch which can run and keep time. However, it requires an additional movement module called the PalanKing to wind and set it, which brings the total thickness back up to the relatively hulking 3.75mm. Does this disqualify it?

If a future production model manages to remedy the need for the PalanKing, then it may indeed be the undisputed champion. The fact that Konstantin Chaykin was willing to share this prototype with the world however was an incredibly bold move, as it will make the likes of Piaget, Bulgari, and Richard Mille scramble to break the record for the thinnest mechanical watch once again.