Rolex Datejust 31 vs Tudor Black Bay
Ref. M278274-0018 vs Ref. M79230B-0008
The Rolex Datejust 31 and Tudor Black Bay represent one of the most compelling matchups in luxury watches — a sibling rivalry between two brands under the same parent company. With the Rolex Datejust 31 priced at $10,750 and the Tudor Black Bay at $4,100, the price gap raises a critical question: does the extra investment in the pricier option deliver proportional value? We break down the specs, market performance, and flip potential to help you decide.
Price Comparison
Rolex
Datejust 31
Tudor
Black Bay
At retail, the Rolex Datejust 31 is listed at $10,750 while the Tudor Black Bay comes in at $4,100. The Tudor Black Bay comes in at $6,650 less — more than half the price difference — making it a significantly more accessible option. On the secondary market, the gap narrows: the Rolex Datejust 31 trades around $10,000 and the Tudor Black Bay around $3,690, a difference of $6,310 favoring the Tudor Black Bay. Currently holding steady at just 7% below retail, this watch retains most of its value on the secondary market. The Tudor Black Bay shows a more modest market premium of -10.0%, holding steady. For investors, the Rolex Datejust 31 edges ahead with a flip potential score of 3/10 compared to 2/10.
Specifications
| Specification | Rolex Datejust 31 | Tudor Black Bay |
|---|---|---|
| Case Diameter | 31mm | 41mm |
| Case Thickness | 11.3mm | 12.7mm |
| Case Material | Oystersteel and 18ct white gold | Stainless steel |
| Bezel | 18ct white gold, fluted | Unidirectional rotating bezel with anodized aluminium insert in blue |
| Crystal | Sapphire with Cyclops lens | Domed sapphire crystal |
| Water Resistance | 100m / 330ft | 200m / 660ft |
| Movement | Rolex calibre 2236 | Tudor Calibre MT5602 |
| Movement Type | Automatic | Automatic |
| Power Reserve | 55 hours | 70 hours |
| Bracelet/Strap | Jubilee, five-piece links | Stainless steel with riveted-style links |
| Clasp | Oysterclasp with Easylink 5mm comfort extension | Folding clasp with safety catch and micro-adjustment |
| Lug Width | 16mm | 22mm |
Key specification differences stand out between these two: The Tudor Black Bay leads in water resistance (200m / 660ft vs. 100m / 330ft), and the Tudor Black Bay offers longer power reserve at 70 hours, and the Rolex Datejust 31 uses Oystersteel and 18ct white gold while the Tudor Black Bay opts for Stainless steel. With 8 notable spec differences in total, the choice depends on which features matter most to your use case.
Value Per Feature
Per millimeter of case diameter, the Rolex Datejust 31 costs $323 versus $90 for the Tudor Black Bay. For water resistance, the Tudor Black Bay delivers better value per meter of depth rating. The Tudor Black Bay offers more power reserve per dollar spent.
Which Should You Buy?
Choose the Rolex Datejust 31 if you value stronger flip potential, better value retention. Go with the Tudor Black Bay if you prioritize a lower entry price, serious diving capabilities. For pure investment potential, the Rolex Datejust 31 has the edge based on current market data.
Frequently Asked Questions
Which is more affordable, the Rolex Datejust 31 or the Tudor Black Bay?
The Tudor Black Bay is more accessible, priced at $4,100 compared to $10,750.
Which watch is a better investment?
Based on current market data, the Rolex Datejust 31 has a higher flip potential score of 3/10, suggesting stronger investment returns. However, watch values can fluctuate based on market conditions.
Which holds its value better on the secondary market?
The Rolex Datejust 31 currently trades at 7.0% below retail, indicating moderate value retention on the pre-owned market.
How do the Rolex Datejust 31 and Tudor Black Bay compare in size?
The Rolex Datejust 31 measures 31mm in diameter and 11.3mm thick, while the Tudor Black Bay is 41mm by 12.7mm. Water resistance differs too: 100m / 330ft versus 200m / 660ft.
What movements do these watches use?
The Rolex Datejust 31 uses the Rolex calibre 2236 with 55 hours power reserve, while the Tudor Black Bay runs on the Tudor Calibre MT5602 offering 70 hours of power reserve.