Audemars Piguet Royal Oak 15400ST Review: 41 mm Steel Guide (2026)

The Audemars Piguet Royal Oak 15400ST is the 41 mm steel self-winding Royal Oak made from 2012 to 2019: a 9.8 mm thick case with the octagonal bezel and eight hexagonal screws, a Grande Tapisserie dial with a date at 3, the in-house calibre 3120 and an integrated steel bracelet. It replaced the 39 mm 15300ST, was itself replaced by the 15500ST and then the current 15510ST, and sits between the thin 39 mm 15202ST "Jumbo" and the 41 mm chronograph in the Royal Oak range. This guide covers the specifications, the four steel dial colours, what changed from the 15300ST and what the 15500ST changed afterwards, how the watch wears, dealer prices in 2026 and what to check before buying one that is now between 7 and 14 years old. Bizak & Co. sources the 15400ST to order; the Royal Oak collection lists the configurations we can seek.

Last reviewed on October 4, 2026 by Filip Biczak. Prices are dated observations, not quotes.

Audemars Piguet Royal Oak 15400ST specifications

Sources: the Audemars Piguet collection page for the current 41 mm self-winding Royal Oak that succeeded this reference, and Audemars Piguet services for the service and authentication policy that applies to discontinued references.

What is the Royal Oak 15400ST?

Audemars Piguet introduced the 15400ST in 2012, the Royal Oak's 40th anniversary year, as the everyday self-winding Royal Oak in steel. The brief was simple: take the 39 mm 15300ST, enlarge the case to 41 mm, keep the calibre 3120 and modernise the dial. The result is the Royal Oak most people picture when they think of a modern steel example: the large-pattern Grande Tapisserie dial, the applied "AP" monogram at 12 with "Audemars Piguet" and "Automatic" printed beneath it, baton markers with luminous inserts and a date at 3 with a white frame. The 15400ST was made alongside the thinner 15202ST Jumbo and the 15450ST at 37 mm, and for seven years it was the steel Royal Oak that a first-time buyer could expect to find at a boutique. It left the catalogue in 2019 when the 15500ST arrived, so every 15400ST on the market today is pre-owned.

Which 15400ST dial: black, silver, blue or slate grey?

All four share the same case, movement and bracelet, so the choice is taste and budget. The blue dial carries the largest premium because it is the colour buyers associate with the Royal Oak; the black and silver dials usually cost less for the same year and condition, and the slate grey sits between them depending on how many are offered at a given time. Beware of listings that describe the silver-toned .02 as a "white" dial without photographs: the dial is silver with a visible guilloche pattern, not flat white.

What changed from the 15300ST to the 15400ST?

• Case size. The 15300ST is 39 mm; the 15400ST is 41 mm. Thickness grew a fraction, from about 9.4 mm to about 9.8 mm, because the larger case needed a deeper dial and bezel.
• Dial text. The 15300ST carries "Audemars Piguet" in applied letters at 12; the 15400ST moved to the applied "AP" monogram at 12 with the brand name printed beneath it, the layout AP still uses.
• Markers and hands. The 15400ST's baton markers and hands are longer and bolder to suit the larger dial, and the date window moved slightly outward.
• Movement. Unchanged. Both use the calibre 3120, visible through the sapphire case back with its 22 ct gold rotor.
• Bracelet. The 15400ST's integrated bracelet is wider at the case to match the 41 mm lugs and uses the AP folding clasp.

The 15300ST remains the choice for buyers who find 41 mm too much; the 15400ST is the one for buyers who want the modern dial and a watch that reads as current from across a room. The 15300ST guide covers the smaller watch in detail.

15400ST vs 15500ST vs 15510ST: which 41 mm Royal Oak?

The 15400ST is the thinnest of the three and the one with the classic dial layout. The 15500ST and 15510ST gained the calibre 4302, with a longer power reserve and a higher beat rate, at the cost of about 0.6 mm in thickness and a busier dial. Buyers who prize the slimmer profile and the older-style dial choose the 15400ST; buyers who want the newest movement and a boutique warranty choose the 15510ST. The 15500ST review and the 15510ST guide cover the successors.

15400ST or 15202ST Jumbo?

The two steel Royal Oaks are often cross-shopped and should not be. The 15202ST is 39 mm and about 8.1 mm thick with the ultra-thin calibre 2121, a Petite Tapisserie dial and no seconds hand; it is the direct descendant of the 1972 original and costs roughly twice as much on the secondary market. The 15400ST is a larger, thicker, more robust everyday watch with a seconds hand, a longer power reserve and a far wider choice of dials. If you want the historical Royal Oak and have the budget, read the 15202ST guide; if you want a modern steel Royal Oak to wear every day, the 15400ST is the better value.

How does the Royal Oak 15400ST wear?

At 41 mm with an integrated bracelet, the 15400ST wears larger than its diameter suggests because the bezel is wide and the bracelet runs straight out of the case. The lug-to-lug is short, so it fits wrists from about 16.5 cm (6.5 inches) upward; on smaller wrists the 39 mm 15300ST or the 37 mm 15450ST sit better. At about 9.8 mm thick it slides under a shirt cuff, which the thicker 15500ST and 15510ST do less easily. The bracelet tapers from the case to the clasp and the links articulate well, but it has no micro-adjustment, so sizing is by half links. The brushed surfaces and polished chamfers mark easily, and a watch that has been worn daily for a decade will show it on the bezel edges and the top of the bracelet links.

How much is a Royal Oak 15400ST? Dealer prices in 2026

• Retail. The 15400ST has been discontinued since 2019, so there is no current list price. Audemars Piguet's current 41 mm self-winding Royal Oak is the 15510ST, whose price is published on the AP collection page linked above and sets the ceiling for what a pre-owned 15400ST should cost.
• Secondary market. Through 2025 and into 2026, pre-owned 15400ST examples have generally been asked at a premium to the price they sold for new, with the blue dial at the top, black and silver below it, and the grey depending on availability. Full sets with box, papers and extract command more than watch-only examples.
• Bizak catalogue asks. On October 4, 2026 our sourced catalogue listed four pre-owned steel 15400ST examples: the black dial at US$34,913, the silver-toned dial at US$27,899, the blue dial at US$49,183 and the slate grey dial at US$42,461, all sourced to order. The spread reflects dial colour, year, condition and what comes with the watch.

Those figures describe what we saw on that date and will move. Ask for a dated quote for the exact dial, year and set; our Audemars Piguet price guide explains how to read a quote against the market.

Is the Royal Oak 15400ST a good buy?

For a buyer who wants a steel Royal Oak at 41 mm, the 15400ST is the sensible route. It is cheaper than the 15510ST, thinner, and carries the dial layout many collectors prefer. The calibre 3120 is a proven movement with a long service history, and parts and service remain available through Audemars Piguet. The watch has held value well since discontinuation because demand for steel Royal Oaks exceeds supply at every price level. Buy it for the watch rather than for a short-term gain, and buy the best example you can find rather than the cheapest.

Buying a used 15400ST: what to check

• Reference and dial. Confirm the full reference on the case back and papers: 15400ST.OO.1220ST followed by .01, .02, .03 or .04. Match the dial colour in the photographs to that suffix; dials were not swapped at the factory.
• Case finishing. The chamfers on the bezel and case should be bright and sharp with a clear line between brushed and polished surfaces. Rounded chamfers or softened screw heads mean polishing, which lowers value.
• Bezel screws. The eight white gold hexagonal screws should align in the same orientation and show no tool marks.
• Bracelet. Check for stretch between links, for scratches on the top surfaces and for a clasp that closes with a positive click. A bracelet that has lost several links limits who can wear the watch.
• Movement. Through the case back, the gold rotor should be undamaged and the finishing clean; ask for the date of the last service and whether it was done by Audemars Piguet.
• Papers. The warranty card should carry the full reference and a serial matching the case. An AP extract from the archives can confirm an undocumented watch.
• Price against the band. A full-set blue dial offered well under the market is the single most reliable warning sign.

Our authentication process describes what we inspect before dispatch, and the Royal Oak authentication guide goes deeper on dials and cases.

Quick answers

What is the Audemars Piguet Royal Oak 15400ST?

The 41 mm steel self-winding Royal Oak made from 2012 to 2019, with the calibre 3120, a Grande Tapisserie dial with date and an integrated steel bracelet. It replaced the 39 mm 15300ST and was succeeded by the 15500ST.

How much is a Royal Oak 15400ST?

There is no current retail price because the reference is discontinued. Bizak's sourced catalogue listed four pre-owned steel 15400ST examples between US$27,899 and US$49,183 on October 4, 2026, sourced to order, with the blue dial at the top.

What is the difference between the 15400ST and 15500ST?

The 15400ST uses the calibre 3120 with about 60 hours of reserve in a 9.8 mm case; the 15500ST uses the calibre 4302 with about 70 hours in a 10.4 mm case, with thicker markers and the date moved to the dial edge. Both are 41 mm steel.

Which 15400ST dial colours were made?

Four in steel: black (.01), silver-toned (.02), blue (.03) and slate grey (.04). The blue is the most requested and the grey the least common.

Is the 15400ST thinner than the 15510ST?

Yes. The 15400ST is about 9.8 mm thick against about 10.4 mm for the 15510ST, because the calibre 3120 is slimmer than the calibre 4302.

Request a Royal Oak 15400ST sourcing quote

Tell us the dial colour, preferred year range, condition and whether box and papers are required, plus your budget and timing, through our sourcing enquiry form. We confirm the specific watch, photographs, papers and final price before you commit. Catalogue entries: 15400ST black dial, 15400ST silver-toned dial, 15400ST blue dial, 15400ST slate grey dial; browse the Royal Oak collection or sell or trade your Royal Oak.

Related reading: Royal Oak 15202ST Jumbo guide · Royal Oak 15510ST guide · Royal Oak Chronograph 26331ST guide · Audemars Piguet price guide.