The 2021 stainless-steel Audemars Piguet Royal Oak Offshore Diver, reference family 15720ST, keeps the familiar 42 mm case and 300 m stated water resistance but updates the movement, dial details, ceramic crowns and strap attachment. Its reported launch prices varied by market and publication: $25,400 in Hodinkee’s US account, while Swiss-franc figures differed between two 2021 reports.
What changed on the 2021 Royal Oak Offshore Diver?
The 15720ST is an evolution of the preceding steel 15710ST, not a wholesale redesign. Both retain the broad 42 mm format, Méga Tapisserie dial, internal rotating bezel and rubber strap. The earlier 15710ST used Calibre 3120; the 2021 update introduces Calibre 4308 and revises several visible and practical details. Monochrome Watches’ 2021 launch coverage describes the update as an evolution.
- Movement: in-house automatic Calibre 4308 replaces Calibre 3120.
- Crowns: the screw-locked crowns are black ceramic.
- Dial: revised markers and date placement accompany a larger applied AP logo.
- Timing scale: the first 15 minutes of the internal rotating bezel have a contrasting treatment intended to improve legibility.
- Strap: a quick-release system makes the rubber strap interchangeable.
- Finishing: launch coverage notes more refined finishing while preserving the established case proportions.
These are launch-era descriptions, not a claim that every detail was independently assessed hands-on. Peter Chong’s Deployant review describes the watch as bold with strong wrist presence and says its case and pliable rubber strap felt comfortable to him; those are one reviewer’s impressions, not a universal fit assessment.
Is the 2021 Offshore Diver 42 mm?
Yes. The 15720ST has a 42 mm stainless-steel case. Monochrome’s launch specifications give its height as 14.1 mm; Deployant lists the 42 mm diameter but does not state a height in the specification block retrieved. The design pairs an octagonal external steel bezel with an internal rotating dive-time scale and two screw-locked crowns.
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Launch sources state water resistance of 300 m. That is the watch’s stated specification, not a reason to use an individual watch for diving without confirming its condition and service status. Sapphire is used for the front crystal and display caseback. The dial has a Méga Tapisserie pattern, applied gold markers, luminous Royal Oak hands, central seconds and a date display.
Calibre 4308 specifications
The self-winding Calibre 4308 is the central technical change. Launch specifications describe it as a 32 mm-diameter, 5.2 mm-thick movement with 234 parts and 32 jewels. It runs at 28,800 vibrations per hour, or 4 Hz, and has a minimum power reserve of 60 hours. Hodinkee’s 2021 introduction and the other launch reports identify the 4308 in the new steel Diver.
Rank #2
- Fits for Most Audemars Piguet Watch Model Collection: Royal Oak, Offshore Diver 42 MM, 15707, 15703, 25721, 26470, 26178OK...etc.
- It fit all version of Royal Oak Offshore which takes smaller lenght tube.
- Screws: 26.5 mm X 17.5 mm X 1.6 mm
- Packing: 2 pcs tubes and 2 pcs screws
- Material: They are made of the highest quality 316L stainless steel.
Which 15720ST versions launched in 2021?
The initial steel collection offered three dial-and-strap combinations. Each configuration came with a second rubber strap, according to Monochrome’s launch report. The extra strap varied by version:
| Reference | Dial and markers | Fitted strap | Additional strap |
|---|---|---|---|
| 15720ST.OO.A052CA.01 | Khaki green dial; pink-gold markers and hands | Green rubber | Black rubber |
| 15720ST.OO.A027CA.01 | Navy blue dial; white-gold markers and hands | Blue rubber | Black rubber |
| 15720ST.OO.A009CA.01 | Grey dial; white-gold markers and hands | Grey rubber | Blue rubber |
Monochrome reported that the watches were expected in boutiques and retailers in May 2021. The package details describe the original launch configurations; they do not establish current accessory stock or compatibility of third-party straps.
Rank #3
- Compatible Model: Fits for Most Audemars Piguet Watch Model Collection: Royal Oak, Offshore Diver 42 MM, 15707, 15703, 25721, 26470, 26178OK...etc.
- This tube and screw are made of 316L stainless steel, offering durability and strength for your watch.
- Size: (24mm x 1.6mm x 1.2mm) M1.2mm
- Package Includes:2 Tubes,2 Screws
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How much did the 15720ST cost at launch?
Published 2021 launch prices differ. Treat these as historical reports, not current retail or resale prices:
| Source and date | Reported launch price | Qualification |
|---|---|---|
| Monochrome Watches, 18 March 2021 | CHF 21,650 | Excluding taxes |
| Hodinkee, 30 March 2021 | US$25,400 | US launch price |
| Deployant, 2 April 2021 | CHF 23,400 | Reported retail price |
The two Swiss-franc reports do not explain their difference, so there is no supported basis for reconciling them into one definitive CHF figure. Audemars Piguet’s current official page for the khaki reference identifies the model and provides a boutique-finding option, but its retrieved page text does not give a readable price. It therefore does not establish a current price, live stock, or a secondary-market range.
Rank #4
- Compatible Brand: Audemars Piguet Royal Oak Offshore
- Size：3.0*1.4*4.6mm
- Premium Material: Made From 316L Stainless Steel. Corrosion-Resistant, Durable, And Outperforms Alloy Alternatives.
- Package Included: 4 Screws
- Your Satisfaction Is Our Highest Priority. Pls Contact Us If You Have Any Questions, We Will Try Our Best To Serve For You.
What the launch reports establish—and what they do not
The documented case size, movement figures, water-resistance rating and historical prices describe launch-era specifications and reporting. They do not establish sales volumes, production totals, resale performance or price appreciation. Nor do the included interchangeable straps verify that a particular replacement strap is available now or will fit.
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
