Rolex
Rolex Datejust 31 278240
The Rolex Datejust 31 (reference 278240) is a 31 mm Oystersteel watch. It runs on the automatic caliber 2236 with a 55-hour power reserve and is water resistant to 100 m.
Specifications
Case
- Reference
- 278240
- Collection
- Datejust
- Case size
- 31 mm
- Case material
- Oystersteel
- Case shape
- Round
- Crystal
- Sapphire
- Water resistance
- 100 m
- Bracelet / strap
- Oystersteel
Dial and bezel
- Bezel
- Domed
Movement
- Movement
- Automatic
- Caliber
- 2236
- Power reserve
- 55 hours
- Frequency
- 28,800 vph
- Functions
- Date
Production
- Production
- Current
Dial versions
This reference was made with these dials and finishes.
278240 Black
278240-0001
Lacquer
278240 Blue
278240-0017
Bright blue; Sunray
278240 Grey
278240-0009
Dark grey; Sunray
278240 Pink
278240-0007
Sunray
278240 Silver
278240-0005
Sunray
278240 White
278240-0003
White
How it compares within the Datejust family
Side by side with other references in the same collection, from the catalog.
| Reference | Size | Material | Dial | Caliber | Years |
|---|---|---|---|---|---|
| 278240 (This watch) | 31 mm | Oystersteel | — | 2236 | — |
| 126200 | 36 mm | Oystersteel | — | 3235 | 2018– |
| 126233 | 36 mm | Yellow Rolesor (Oystersteel/18k yellow gold) | — | 3235 | 2018– |
| 126234 | 36 mm | White Rolesor (Oystersteel/18k white gold) | — | 3235 | 2018– |
| 126284RBR | 36 mm | Oystersteel / White gold | — | 3235 | — |
| 126300 | 41 mm | Oystersteel | — | 3235 | 2017– |
| 126331 | 41 mm | Everose Rolesor (Oystersteel/18k Everose gold) | — | 3235 | 2017– |
| 126333 | 41 mm | Yellow Rolesor (Oystersteel/18k yellow gold) | Champagne / Black / Silver / Blue / Wimbledon slate / various | 3235 | 2017– |
| 126334 | 41 mm | White Rolesor (Oystersteel/18k white gold) | — | 3235 | 2017– |
About the Datejust family
The Datejust appeared in 1945 as the first self-winding wristwatch to show the date in a window, together with the Jubilee bracelet designed for it. The Cyclops magnifier over the date followed in the 1950s, and the combination of fluted bezel, date window and Jubilee bracelet has stayed the model's signature ever since.
The catalog covers several generations, from caliber 3135 references to the current 3235 models: the Datejust 41, such as refs. 126300, 126331 and 126333, and the Datejust 36, such as refs. 126200, 126233 and 126234. Variants combine steel, Rolesor and gold with smooth or fluted bezels, Oyster or Jubilee bracelets and a very wide choice of dials. For dealers the exact dial, bezel and bracelet combination is what separates otherwise similar watches, so they are always described together.
Quick answers
- What size is the Rolex Datejust 31 278240?
- The Rolex Datejust 31 278240 has a 31 mm case.
- What movement does the Rolex Datejust 31 278240 use?
- It uses the automatic caliber 2236, with a 55-hour power reserve.
- How water resistant is the Rolex Datejust 31 278240?
- It is water resistant to 100 metres.
- Is the Rolex Datejust 31 278240 still in production?
- Yes, it is a current reference.
- What is the Rolex Datejust 31 278240 made of?
- The case is Oystersteel. Bracelet or strap: Oystersteel.
- Which dials was the Rolex Datejust 31 278240 made with?
- The catalog lists 6 dials: Black, Blue, Grey, Pink, Silver, White.
Catalog facts checked October 2026.