The Piaget Altiplano Ultimate 900P is just 3.65mm thick yet still looks like an actual watch The Piaget Altiplano Ultimate 900P is just 3.65mm thick yet still looks like an actual watch

The Piaget Altiplano Ultimate 900P is just 3.65mm thick yet still looks like an actual watch

Zach Blass

I have been very happy to see ultra-thin watchmaking make a comeback as of late, but the race to be the thinnest does have its concessions. For Richard Mille, to achieve the ‘thinnest mechanical watch in the world’ title it, in my opinion, had to sacrifice looking like an actual wristwatch – more like a wrist cuff. Do not get me wrong, incredible engineering to realize that Richard Mille. But, for me, the real achievement is to reach ultra-thinness within a form that truly resembles a watch aesthetically and dimensionally speaking. Piaget did an incredible job with the now third-place-for-thinnest Altiplano Ultimate Concept watch, just 2mm thick. This, however, is a well-into-the-six-figures timepiece. Now, a 3.65mm thick watch may not be as mind-blowingly thin as a 2mm thick watch, but the Altiplano Ultimate 900P is the first watch I have ever owned that is genuinely deserving of the ‘slips under the cuff with ease’ buzzphrase. And it actually looks like a wristwatch, a handsome one at that.

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The case

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First introduced in 2013 for Piaget’s 140th anniversary, the Piaget Altiplano Ultimate 900P has only ever been made available in both rose and white gold cases measuring a modern yet very wrist-manageable 38mm case just 3.65mm thick and 41.9mm lug-to-lug. At the time of its introduction, it was the thinnest mechanical watch in the world. The entire front and side of the case are rendered in an elegant mirror finish befitting of such a design, with only the solid case back given a radial brush. This may sound completely and utterly crazy, but the brushing, in my opinion, increases the comfort of the caseback against the skin as it creates a certain grip and does not have that glossy feel. This is a watch, again, in my opinion, best worn more snugly on the wrist as it would defeat the purpose of the ultra-thin exercise to have the watch dangling off of your arm. With it worn snug, you can really feel the caseback against your wrist, its thinness offering the experience of a watch as a second skin, so a smoother polished surface as you perspire would not feel as great. Most dress watches utilise a polished caseback when solid, but think about the bubbled-back of every Rolex Oyster Perpetual model with its sloped polished ring leading up to a flat brushed surface. This is not random, it is intentional.

Most watches have a cambered shape to their case, some more subtle and others more dramatic like a Tank Cintrée. Ultra-thin watches, by nature, need to be more flat – running the risk of wearing like a pie pan on the wrist. The cambered curvature of a case helps better wrap a watch around your curved wrist. The 900P’s case is ultimately very flat, understandably, but the short lugs drop down at their end to create a sort of grip that simulates a camber in some respects. The shorter lug-to-lug length also means that the watch, more likely than not, will not extend out to the portion of your wrist where it rounds and curves down. The second skin feeling I mentioned earlier is no joke, this watch really feels like an extension of your body while worn.

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While I may have worn the watch daily for weeks in the honeymoon phase after I acquired it last year, and while it was one of my most worn watches in 2023, this is definitely not a ‘daily wearer’ within a collection or for a typical individual. With a 20-metre water-resistant case, it is not like you need to take the watch off while washing your hands or if you find yourself outside during a light drizzle. But, ultimately as a truly ultra-thin watch, the Piaget Altiplano Ultimate 900P is not something you want to accidentally mash into a doorknob. Part of the reason the watch is so thin is that the caseback actually serves as the mainplate for the movement. Also, being so thin, the case itself, at a micro-scale, is capable of flexing. Perhaps the reason the model has not been introduced in yellow gold is due to the more malleable nature of gold in its purer form.

The dial

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With this flexibility of the case due to its thinness, and in the pursuit of ultra-thinness, all of the components of the watch and their placement had to be very strategic to save precious millimeters in height. One step to achieve this was to have an off-centred sub-dial, approximately 3/4 of the entire front real estate, display simply the hours and minutes through a recessed chapter ring. You’ll notice that all of the sensitive components find themselves fractionally beneath the surface of the 900P movement’s bridges. While the sapphire crystal is just fractions of a millimetre thick, the flexibility of the case means that under enough stress were the components left unprotected the glass could theoretically come into contact with components like the hands or wheels – which would be disastrous of course. In its realized design, in the unlikely worst-case scenario, the sapphire crystal can only come into contact with the metal of the bridges preventing the stoppage of the movement.

There are now various dial configurations for the Altiplano 900P Ultimate, in which the colour of the dial ring and bridges can vary. This reference, biasedly my favourite, has darkened black bridges with a dial ring made of rose gold to match the case. The exposed and openworked nature of the movement offers a very technical aesthetic, but the darkened nature of the movement makes it appear more sleek and fashion-forward and also enhances the pop of the rose gold accents of the hands and dial ring. This not only looks really good, but it also increases legibility. Speaking of legibility, with such a thin bezel the dial can be larger. Typically this might make you perceive the watch as larger than it is, but the compact lug-to-lug mitigates this effect. Plus, with the dial really being the main event here visually, it really works in the design’s favour.

The strap

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With such a luxurious watch some might have expected a deployant clasp, but to use one for this watch, in my opinion, would be criminal to its purpose. Deployant clasps by nature add bulk and thickness, counterintuitive for the wear experience objective of the Piaget Altiplano 900P Ultimate. The wide leather strap, colour-matched to the darkened 900P movement, is nice and thin. Again, a tapered padding to the strap would have been really silly for a 3.65mm thick watch. The pin/buckle as well is thin, yet sturdy, and when the strap is secured to the wrist the underside of the watch has an equally slim profile as the case on top of your wrist. This really aids in the ‘slide under the cuff’ aspect of the watch.

The movement

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By today’s standards, 48 hours of power reserve is nothing special per se. For a watch of this size, however, the fact the manually wound calibre can last two days without a wind is rather remarkable. It is also remarkable that while so thin, all of the components have been decorated at a fine level with chamfers to the bridges, and solarisation to the wheels, dial ring, and top of the bridges. In configurations where the bridges are not darkened, the glisten of the bevels definitely comes through more whereas in this darkened configuration the finishes are muted. Left untreated or undarkened, however, the winding works, gear train, and balance are all in full view. This watch, even without a running second hand, never feels static. It is always alive from the front while wound and worn.

The verdict

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I find the Piaget Altiplano Ultimate 900P does not always get the credit it is due. Born at a time when the sports watch craze was about to kick off, the focus shifted away from dressier timepieces to divers and luxury integrated sports watch designs. A year after its introduction, the Bulgari Octo Finissimo would debut in 2014 – taking the ultra-thin spotlight with a sportier design that was just 5.15mm thick. The ultra-thin race we have watched unfold over the last few years really would not have happened without Piaget’s longstanding passion for ultra-thin watchmaking, their stake in the field cemented with the launch of their legendary 9P movement in 1957 – one of the thinnest movements at the time at just 2mm thick and used by many brands, like Cartier, to achieve their thin creations. The 9P’s 2mm thickness is also what inspired Piaget to create the Altiplano Ultimate Concept watch that, as a whole, is just 2mm thick.

I get that the fragility associated with such a thin watch may worry or deter some. But, from my experience over the last six months, I have comfortably worn this watch frequently in my daily life as a journalist – whether typing away at my laptop, attending brand and collector events here in NYC, and even on press trips like Dubai Watch Week in which I wore the watch daily for a week whether in a t-shirt and pants or a full suit. The wear experience of such a thin watch is incredible in feel, and aesthetically speaking the fact that the dial balances the technical and visual in such a handsome way that the watch looks dapper enough for a tuxedo while also affording a full view of the movement is sensational.

Piaget Altiplano Ultimate 900P pricing and availability

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The Piaget Altiplano Ultimate 900P is available now via Piaget boutiques and authorised dealers, along with Piaget’s e-commerce platform. Price: Upon request (historically configurations range between US$20,000 – US$30,000)

Brand Piaget
Model Altiplano Ultimate 900P
Case Dimensions 38mm (D) x 3.65mm (T) x 41.9mm (LTL)
Case Material 18k rose gold
Water Resistance 20m
Crystal Sapphire crystal
Dial Off-centred 18K rose gold chapter ring dial
Strap Leather strap w/ 18k rose gold pin/buckle
Movement In-house hand-wound 900P
Power Reserve 48 hours
Functions Hours, minutes
Availability Available now
Price Upon request

Editor’s note: This is not a prototype or press sample, it is Zach’s actual watch he himself purchased for his collection.