Datejust 31 Stainless Steel Domed / Oyster / Blue Roman

About This Watch

The Rolex Datejust 31, a timeless embodiment of the brand’s legacy of precision and elegance, finds a striking expression in its blue Roman dial variant. Introduced in 1945, the Datejust collection has long symbolized the intersection of horological innovation and enduring sophistication, and this 31mm iteration refines that tradition with a focus on subtlety and refinement. The dial’s deep blue hue, rendered with a lustrous finish, pairs seamlessly with the crisp, hand-finished Roman numerals and slender stick hands, creating a composition that balances classicism with modern restraint. Encased in polished stainless steel, the domed Oyster case—engineered for durability and water resistance to 100 meters—adds a tactile dimension to its understated presence, while the sapphire crystal protects the dial with unobtrusive clarity. At its heart lies the Caliber 2235, a self-winding movement celebrated for its reliability and the inclusion of a date display that operates with seamless precision. This mechanical complexity is concealed beneath the closed case back, a deliberate choice that emphasizes the watch’s wearability as much as its craftsmanship. The Datejust 31’s proportions—its 31mm diameter and 16mm lug width—ensure it sits comfortably on the wrist, making it as practical for everyday wear as it is appropriate for formal occasions. This watch is for those who value discretion as much as excellence, seeking a timepiece that speaks volumes without overt flourish. It suits the discerning individual who appreciates the quiet confidence of a well-crafted instrument, one that endures as both a companion and a testament to legacy.

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. 48 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.

178240-0036 is one of 24 executions of the 178240 base reference. Underneath they are the same watch; what separates this one is a blue dial and a stainless steel case.

Rolex

Grey · Stainless Steel

178240-0001 · 31 mm

Rolex

Silver · Stainless Steel

178240-0005 · 31 mm

Rolex

Grey · Stainless Steel

178240-0006 · 31 mm

Rolex

Black · Stainless Steel

178240-0011 · 31 mm

Rolex

White · Stainless Steel

178240-0015 · 31 mm

Rolex

Black · Stainless Steel

178240-0016 · 31 mm

Rolex

Pink · Stainless Steel

178240-0017 · 31 mm

Rolex

Black · Stainless Steel

178240-0019 · 31 mm

+ 15 more variants in this family.

The 2235 is the small Rolex automatic of the six-digit generation, a 20 mm movement with a date. It carried the Datejust 31 and the 26 mm Lady-Datejust from around 2000 until the 2236 replaced it. It powers 733 watches in this library. It has 31 jewels, a 48-hour reserve and a beat of 28,800 vph, and every one is a COSC chronometer. It is the same architecture as the [2236](/calibers/rolex-2236) that followed, without the silicon Syloxi hairspring and with seven hours less reserve; the [2236 piece](/blog/the-rolex-2236-the-most-common-movement-in-this-library) explains what changed. The library finds it almost entirely in the [Datejust 31](/brands/rolex/datejust-31): 682 references, the 1782xx generation, whose 45 base references and hundreds of dial variants make that collection the largest here. The 26 mm [Lady-Datejust](/brands/rolex/lady-datejust) of the 1791xx generation accounts for 29, the [Pearlmaster](/brands/rolex/pearlmaster) 29 mm and 34 mm for 19, and the 35 mm Yacht-Master for 3. A six-digit Datejust 31 reference is a 2235; the seven-digit one is a 2236, as the [reference-number guide](/blog/how-to-read-a-watch-reference-number) explains. The 2231 was its no-date sibling in the Oyster Perpetual, and the [3135](/calibers/rolex-3135) its counterpart in the 36 mm cases.

732 other watches in the library run the Rolex 2235.

Rolex

Datejust 31 Yellow Gold Diamond / Oyster / Black MOP

178158-0056 · 31 mm

Rolex

Datejust 31 Stainless Steel Diamond / Oyster / Pink MOP

178384-0061 · 31 mm

Rolex

Datejust 31 Rolesor Everose Domed / Jubilee / Black MOP

178241-0043 · 31 mm

Rolex

Datejust 31 Yellow Gold Domed / Oyster / Champagne Roman

178248-0079 · 31 mm