Rolex Datejust 31 · Ref. 278240 · 16mm lug · 31mm case
At a Glance
| # | Best For | Strap | Material | Thickness |
|---|---|---|---|---|
| 1 | Overall / First Purchase | Grey Saffiano Strap for Cartier Tank | Saffiano Calfskin | 2.2mm |
| 2 | Dressy / Formal | Matte Black Alligator Strap for Cartier Tank | Alligator | 2.2mm |
| 3 | Everyday / Casual | Light Grey Nubuck Strap for Cartier Tank | Nubuck Calfskin | 2.2mm |
| 4 | Minimalist / Refined | Grey Rubberised Leather (Togo) Strap for Cartier Tank | Togo Leather (Rubberised) | 2.2mm |
| 5 | Casual / Relaxed | Green Alcantara Strap for Cartier Tank | Alcantara | 2.2mm |
| 6 | Active / Sporty | Black Rubberised Leather (Togo) Strap for Cartier Tank | Togo Leather (Rubberised) | 2.2mm |
| 7 | Comfort / Wildcard | Matte Grey Storm Alligator Strap for Cartier Tank | Alligator | 2.2mm |
Some dials you glance at. The Rolex Datejust 31 (ref. 278240) is one you study. Its mint green dial with applied Roman numerals, Cyclops date at 3 o'clock, and a domed polished Oystersteel bezel. The 16mm lug width might not be the most common, but the options are deeper than you would expect.
At 31mm across and 11mm thick, the Datejust 31 wears like a watch that was designed to be lived with — not just admired behind glass. The right strap pairing amplifies what this watch already does well.
Here are my 7 picks — and why each one works.
Quick Specs
| Case diameter | 31mm |
| Lug width | 16mm |
| Lug-to-lug | |
| Case thickness | 11mm |
| Water resistance | 100m |
| Crystal | Scratch-resistant sapphire |
| Case material | Oystersteel |
| Movement | Rolex Calibre 2236 |
The 16mm lug width means your options are curated but well-covered. Already know what you're looking for? Browse all Rolex Datejust 31-compatible straps on the Strap Finder →
1. Best Overall — Grey Saffiano Strap for Cartier Tank
Your first strap upgrade should feel like an obvious improvement. This one does.
The Grey Saffiano Strap for Cartier Tank uses saffiano leather — that signature cross-hatch embossed pattern you see on high-end bags and accessories. It is remarkably scratch-resistant and handles moisture better than most leathers, which makes it one of the most practical premium options you can put on a watch. At 2.2mm thick, it balances presence and wearability nicely.
The Rolex Datejust 31's 31mm case is ideally proportioned for this strap. The dress watch aesthetic is enhanced by the refined strap construction. It is the kind of pairing where both the watch and strap look better together than apart.
Once you see it on the wrist, it just clicks.
2. Best Dressy — Matte Black Alligator Strap for Cartier Tank
Formal occasions call for something elevated. This delivers without being flashy.
The Matte Black Alligator Strap for Cartier Tank is crafted from genuine alligator leather — not embossed calfskin, the real thing. Each scale pattern is unique, and the matte finish gives it a refined presence that catches light without being flashy. The leather is supple from the start with minimal break-in needed. At 2.2mm thick, it balances presence and wearability nicely.
Paired with the Rolex Datejust 31's green dial, this strap elevates the overall look without competing for attention. The 11mm case thickness means a padded strap like this one feels proportional and substantial.
3. Best Everyday — Light Grey Nubuck Strap for Cartier Tank
For daily wear, comfort and versatility matter more than anything else.
The Light Grey Nubuck Strap for Cartier Tank is crafted from nubuck leather — soft, velvety to the touch, and comfortable from the first wear. No break-in period needed. The suede-like texture adds a casual warmth that takes the edge off a formal watch without losing sophistication. At 2.2mm thick, it balances presence and wearability nicely.
Paired with the Rolex Datejust 31's green dial, this strap elevates the overall look without competing for attention. The 11mm case thickness means a padded strap like this one feels proportional and substantial.
A combination that's greater than the sum of its parts.
4. Best Minimalist — Grey Rubberised Leather (Togo) Strap for Cartier Tank
Clean lines and no visual clutter — that's the appeal here.
The Grey Rubberised Leather (Togo) Strap for Cartier Tank uses rubberised leather — a material that blends the look and feel of leather with the water resistance and durability of rubber. The smooth finish is clean and modern, and the pastel colour options add a playful element to otherwise serious watches. At 2.2mm thick, it balances presence and wearability nicely.
What makes this pairing work on the Rolex Datejust 31 is the contrast — the refined case finishing against the texture creates visual interest without conflict. With a 31mm case, the proportions stay balanced.
5. Best Casual — Green Alcantara Strap for Cartier Tank
For those days when the Rolex Datejust 31 comes out with jeans and a t-shirt.
The Green Alcantara Strap for Cartier Tank is crafted from Alcantara — the same Italian material used in luxury car interiors and high-end sportswear. It has a suede-like softness that is immediately comfortable, with a luxurious hand feel that belies its toughness. At 2.2mm thick, it balances presence and wearability nicely.
On the Rolex Datejust 31, this strap adds a layer of sophistication that plays well with the dressy aesthetic. The 31mm case at 11mm thick pairs naturally with the padded construction without creating any imbalance on the wrist.
Simple, effective, and genuinely enjoyable to wear.
6. Best Sporty — Black Rubberised Leather (Togo) Strap for Cartier Tank
Not every sporty strap needs to be water-resistant — sometimes it is about the texture and attitude.
The Black Rubberised Leather (Togo) Strap for Cartier Tank uses rubberised leather — a material that blends the look and feel of leather with the water resistance and durability of rubber. The smooth finish is clean and modern, and the pastel colour options add a playful element to otherwise serious watches. At 2.2mm thick, it balances presence and wearability nicely.
Paired with the Rolex Datejust 31's green dial, this strap elevates the overall look without competing for attention. The 11mm case thickness means a padded strap like this one feels proportional and substantial.
Simple, effective, and genuinely enjoyable to wear.
7. The Wildcard — Matte Grey Storm Alligator Strap for Cartier Tank
Think of this as the strap you didn't know you needed.
The Matte Grey Storm Alligator Strap for Cartier Tank is crafted from genuine alligator leather — not embossed calfskin, the real thing. Each scale pattern is unique, and the matte finish gives it a refined presence that catches light without being flashy. The leather is supple from the start with minimal break-in needed. At 2.2mm thick, it balances presence and wearability nicely.
The Rolex Datejust 31's 31mm case is ideally proportioned for this strap. The dress watch aesthetic is enhanced by the refined strap construction. It is the kind of pairing where both the watch and strap look better together than apart.
Once you see it on the wrist, it just clicks.
A Note on Buckle Colour
Quick but important: always match your buckle to your case. The Rolex Datejust 31's Oystersteel case calls for a silver (brushed or polished) buckle. All Delugs leather straps ship with a pin buckle and can be upgraded to a Spring Deployant Clasp for extra security and convenience. All Delugs straps come with quick-release spring bars pre-installed, so swapping straps takes seconds.
How to Change the Strap on Your Rolex Datejust 31
Swapping straps on the Rolex Datejust 31 is one of the easiest upgrades you can make — and with Delugs straps, you don't even need a tool.
All Delugs straps come with quick-release spring bars already pre-installed, so changing straps is completely tool-free. Here's how:
- Prepare your workspace. Lay the watch face-down on a soft cloth or microfiber pad to protect the caseback from scratches.
- Release the spring bar. Locate the small lever on the quick-release spring bar. Pull it back with your fingernail or fingertip to compress the bar.
- Remove the strap. While holding the lever, angle the strap out from between the lugs. Repeat for the other side.
- Insert the new strap. Slide one end of the spring bar into the lug hole. Pull the lever on the quick-release spring bar knob, guide the entire spring bar into the opposite lug hole, and then release the knob. You should hear a small click when the spring bar extends and seats into the lug hole.
- Check the fit. Give the strap a gentle tug to make sure both spring bars are securely locked in. If there's any play, reseat the spring bar.
The entire process takes under a minute once you get the hang of it — no spring bar tool required. The Rolex Datejust 31 uses a standard 16mm lug width, and all Delugs straps in 16mm will fit perfectly.
Frequently Asked Questions
What is the lug width of the Rolex 278240?
The Rolex 278240 has a 16mm lug width. While 16mm is less common than 20mm, there is still a strong selection of quality straps available. All Delugs straps are available in 16mm.
What is the reference number for the Rolex Datejust 31?
The reference number for the Rolex Datejust 31 is 278240. You can find this on the caseback of your watch or on the original paperwork. Knowing your reference number helps ensure you get the right lug width when ordering a strap.
Can I use rubber or casual strap on a Rolex dress watch?
Absolutely. While the Datejust 31 leans dressy, pairing it with a rubber or casual leather strap opens it up for everyday and weekend wear. Many collectors find that a nubuck or waxy leather strap transforms a dress watch into a versatile daily wearer without losing its character.
Do Delugs straps come with spring bars?
Yes — every Delugs strap comes with quick-release spring bars pre-installed. This means you can change straps by hand in seconds, without needing any tools. The quick-release mechanism uses a small lever that you pull with your fingertip to compress the spring bar.
What is the best strap material for the Rolex Datejust 31?
For a dress watch like the Datejust 31, alligator and chèvre leather are the most natural fits — they complement the refined aesthetics without overpowering the watch. For everyday versatility, saffiano and nubuck offer a balance of formality and durability. Our Strap Finder can help narrow down the best option for your style.
Does Rolex use quick-release spring bars?
Most Rolex watches use standard spring bars that require a tool to remove. All Delugs straps come with quick-release spring bars pre-installed, so once you make the switch, future changes are completely tool-free.
Where can I find straps compatible with the Rolex 278240?
The Rolex Strap Finder shows every Delugs strap compatible with the 278240, filtered by lug width and style. You can also use the general Strap Finder to browse by brand, collection, and material. If you need help choosing, our team is available 24/7 via live chat.
Finding Your Strap
The beauty of the Rolex Datejust 31 is that it rewards experimentation. A dressy alligator for the office, nubuck for the weekend — each strap brings out a different side of the watch.
Use the Rolex Datejust 31 Strap Finder to see every compatible strap in one place, filtered to your exact reference. Or if you'd rather explore by feel, the general Rolex Strap Finder lets you browse the full lineup and find your match.
Not sure which strap is right for your specific Datejust 31? Our team is available 24/7 via live chat — drop us a message and we'll help you find the perfect match for your watch, wrist size, and style.
About Delugs
Founded in 2018 and headquartered in Singapore, Delugs is dedicated to elevating the experience of watch ownership through the simple yet powerful act of strap changing. We believe that straps are integral to how a timepiece is worn, perceived, and enjoyed. Our mission is to make strap changing a lifestyle — an everyday act of self-expression and versatility.
Delugs is an independent brand with a global community of clients, with a strong online presence and growing physical retail footprint. Our direct-to-consumer focus keeps us closely connected with the watch enthusiast community — fostering conversations, hosting events, and helping shape a more inclusive and expressive culture around watch collecting. We also work closely with watch brands to craft straps that complement their timepieces, bridging the gap between brand and collector, form and function.
Our catalogue spans leather, rubber, and fabric straps, with options for every watch and every occasion. We are committed to craftsmanship and quality, product design and innovation, and outstanding customer service. We offer watch owners the freedom to change straps as easily as changing outfits, and the opportunity to engage more deeply with the watches they love.
Visit our flagship boutique at Raffles Hotel, Singapore →
— Marcus
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