Audemars Piguet Royal Oak 4100SA 'Tropical'
Audemars Piguet Royal Oak 4100SA: A Time Capsule in Steel and Gold
Nicknamed the "Royal Oak III" by collectors, the reference 4100SA was introduced in 1977 as Audemars Piguet's answer to a growing demand for a smaller, more wearable Royal Oak. Designed by Jacqueline Dimier, it brought the Royal Oak's radical design language, the octagonal bezel, the visible screws, the integrated bracelet, into a more compact 35mm case, while somehow managing to feel just as substantial on the wrist thanks to its bold proportions.
What makes the 4100 truly special, though, is how thin it is. At barely over 7mm, it remains one of the slimmest Royal Oaks ever produced, a genuine feat of case engineering for its time, and a reminder of just how far AP was willing to push the design in its earliest years.
This example is finished in steel and 18k yellow gold, and the dial has aged into a warm, evenly turned tropical brown, the kind of natural, uniform patina that collectors chase and can never be replicated artificially. It is a dial that tells its own story simply through decades of light exposure, and it gives this piece a character no modern reissue could ever match.
Design & Movement
The case and bracelet present in genuine time capsule condition, sharp, honest, and true to its age.
Provenance & Condition
This piece comes as a full set, complete with original inner and outer box and its Certificate of Origin. The certificate does not list a specific production year, though the reference itself was produced from the late 1970s into the early 1980s, placing this example firmly within that golden window of early Royal Oak history.
The Audemars Piguet Royal Oak 4100SA: proof that AP was perfecting proportion and thinness decades before it became fashionable again.
Interested, or have questions about this piece? Send us a DM, we're happy to share more photos, condition notes, or full provenance details.
Brand: Audemars Piguet
Model: Royal Oak
Reference: 4100SA
Bracelet: Stainless steel and 18k yellow gold, integrated
Dial: Tropical brown, evenly aged
Case: Stainless steel and 18k yellow gold
Dimensions: 35mm
Box: yes (inner and outer)
Paperwork: yes (Certificate of Origin)
Year: circa late 1970s to early 1980s