At the beginning of the 1970s, Audemars Piguet was facing dire financial straits like the rest of the Swiss luxury watch industry. As an independent company, however, they had latitude to innovate. It is said that Managing Director Georges Golay called Gerald Genta at 4 PM the day before the Basel Fair asking for a luxury steel sports watch design. Genta's design, delivered the next day, remains the mainstay of his career and the brand to this day A thin but large case with an integrated metal bracelet, an octagonal bezel punctuated with slotted hexagonal nuts, and a simple dial with doubled markers at 12 00. The characteristic bezel is said to be inspired by a diving helmet, and the watch is named for a British sailing ship.

The original Royal Oak (Ref. 5402) was unveiled at the 1972 Basil Fair and was as radical in marketing as in design It was massive compared to other luxury watches and priced far higher than competing models despite being available only in stainless steel. Indeed, the original Ref. 5402 Royal Oak cost as much as ten Rolex Submariners and far more than the company's own gold watches. It measured just 7 mm thick thanks to the Jaeger-LeCoultre-derived Cal. 2121, still one of the thinnest automatic watch movements available. But the case, with its integrated bracelet, was comparatively massive, measuring 39 mm across. The steel case was a novel multi-part design held together by the signature nuts arranged around the bezel, which passed around the movement to be secured to the case back.

The watch was extremely controversial at the time, but Audemars Piguet was able to sell out the initial production run of 1,000 pieces in just over a year. This “A-Series” was followed by another run of 1,000 pieces, then, when sales began to heat up, the company moved to “B” and “C” serial numbers. The original models are distinguished by the “AP” initials at 6 00 on the dial, a design element only duplicated recently with the Ref. 15202. The original “Jumbo” was given a 36 mm companion, the thicker "Mid-Size" Ref. 4100, which sold far better and at a lower price.

In 1992, Audemars Piguet returned to the “Jumbo” design for the "Jubilee" Ref. 14802, which included a display caseback to show the Cal. 2121 in action. This watch was released as a limited edition, with 700 in steel, 280 in yellow gold, and 20 in platinum. Another “Jumbo” model, Ref. 15002, was produced throughout the 1990s without the display caseback and in unlimited numbers.

Audemars Piguet created additional models of the Royal Oak starting in the 1990s, including other “Extra-Thin” reverences. Principal among these is the special Royal Oak Tourbillon line, which uses a larger 41 mm case but is notably thin compared to other tourbillon watches.

Today's "Extra-Thin" Ref. 15202, released in 2000 and updated in 2012 for the 40th anniversary of the model, carries on the tradition of the first Royal Oak, with similar case dimensions and nearly-identical design. Although no longer “Jumbo” (the cheaper Ref. 15400 is 2 mm larger), the “Extra-Thin” is the first choice for traditionalists and connoisseurs. The current Ref. 15202 still uses the original Cal. 2121 movement and has again adopted a display caseback.

• Royal Oak "Jumbo" Ref. 5402 (1972-1990) - 39 mm, Cal. 2121 - The original Royal Oak
• Royal Oak "Jubilee" Ref. 14802 (1992-2000) - Cal. 2121 - 20th anniversary model, LE of 1000, display caseback
• Royal Oak Ref. 15002 (1990-1998) - Cal. 2121 - solid caseback
• Royal Oak "Extra-Thin" Ref. 15202 (2000-present) - Cal. 2121 - display caseback (Also Ref. 15205)

See also the complicated Royal Oak Extra-Thin models

• Royal Oak Tourbillon Extra-Thin Ref. 26510 - 41 mm, Cal. 2924 (Also 26511/26512/26513/26514/26515/26516/26517/26518)
  • Royal Oak Tourbillon Hand-Wound Extra-Thin Ref. 26520 - 41 mm, Cal. 2924-Hand-Wound (Also 26521/26522)
• Royal Oak Perpetual Calendar Extra-Thin Ref. 26586 - 31 mm, Cal. 5133

• Audemars Piguet Royal Oak - The entire model range
• Audemars Piguet Royal Oak Tourbillon - Another Extra-Thin Royal Oak model