Datejust 31 Stainless Steel Diamond / Oyster / Green

In Context

At 31 mm it is small by current standards, in the range most wristwatches occupied before cases began growing through the 1990s. The case back is closed, so the movement stays out of sight, and the sapphire crystal will resist everything short of deliberate abuse. 100 m is genuine swimming resistance — more than the shape of this watch suggests it would need.

The movement winds itself from the motion of your wrist. 55 hours of reserve is enough to set it down on Friday evening and find it still running on Monday. At 28,800 vph the seconds hand advances 8 times a second.

278384RBR-0021 is one of 34 executions of the 278384RBR base reference. Underneath they are the same watch; what separates this one is a green sunburst dial and a white gold, stainless steel case. Introduced in 2020.

Rolex

Black · White Gold, Stainless Steel

278384RBR-0001 · 31 mm

Rolex

Black · White Gold, Stainless Steel

278384RBR-0002 · 31 mm

Rolex

White

278384RBR-0007 · 31 mm

Rolex

White

278384RBR-0008 · 31 mm

Rolex

Grey · White Gold, Stainless Steel

278384RBR-0009 · 31 mm

Rolex

Grey · White Gold, Stainless Steel

278384RBR-0010 · 31 mm

Rolex

White · White Gold, Stainless Steel

278384RBR-0013 · 31 mm

Rolex

White · White Gold, Stainless Steel

278384RBR-0014 · 31 mm

+ 25 more variants in this family.

The 2236 is the Rolex movement inside more watches in this library than any other: 907, in the 28 mm Lady-Datejust and the 31 mm Datejust 31. It was the first Rolex caliber with a silicon hairspring. Introduced in 2014 in the Pearlmaster 34, it is a 20 mm automatic with a date, 31 jewels, a 55-hour reserve and a beat of 28,800 vph, certified by the COSC and then tested again by Rolex after casing to the Superlative Chronometer tolerance of two seconds a day. Its distinction is the Syloxi hairspring: silicon, immune to magnetism, etched to a patented geometry that keeps the spring concentric in every position, and paired with Paraflex shock absorbers. The larger Rolex calibers kept the Parachrom alloy spring; Syloxi did not reach a men's movement until the 7140 of 2023. The [2236 piece](/blog/the-rolex-2236-the-most-common-movement-in-this-library) sets out that history. In the library it powers 488 [Datejust 31](/brands/rolex/datejust-31) references, the seven-digit 2782xx generation of 2020, 399 [Lady-Datejusts](/brands/rolex/lady-datejust) of the 2791xx generation of 2015, 15 [Pearlmasters](/brands/rolex/pearlmaster) and 5 [Yacht-Master 37s](/brands/rolex/yacht-master). The [2235](/calibers/rolex-2235) is the 48-hour movement it replaced, the [2232](/calibers/rolex-2232) its no-date sibling for the Oyster Perpetual, and the [3235](/calibers/rolex-3235) its counterpart in the 36 mm and 41 mm cases.

906 other watches in the library run the Rolex 2236.

Rolex

Lady-Datejust 28 Rolesor Everose Diamond / Oyster / MOP

279381RBR-0014 · 28 mm

Rolex

Lady-Datejust 28 Rolesor Rose Diamond / Jubilee / MOP

279381rbr-0013 · 28 mm

Rolex

Lady-Datejust 28 Rolesor Yellow Domed / Oyster / MOP

279163-0014 · 28 mm

Rolex

Datejust 31 Stainless Steel / Yellow Gold / Diamond / Black MOP / Oyster

278383RBR-0023 · 31 mm