The Tudor Black Bay GMT and the Rolex GMT-Master II do the same job in the same way: both are "true" GMT watches whose local hour hand jumps in one-hour steps, both have a red and blue 24-hour bezel, and both have a power reserve of about 70 hours. The Rolex is slimmer, has a ceramic bezel and a more refined bracelet, and costs several times as much. The Tudor is larger, has an aluminum bezel and twice the water resistance, and is far easier to buy.
So the question is what the extra money buys, and whether it matters to you. We have 34 of the Black Bay GMT 79830RB in stock, from $2,770, and 210 Rolex GMT-Master II watches, from $9,240.
Black Bay GMT vs GMT-Master II at a glance
| Tudor Black Bay GMT | Rolex GMT-Master II | |
|---|---|---|
| Reference | 79830RB | 126710BLRO |
| Case | 41 mm, steel | 40 mm, Oystersteel |
| Movement | MT5652 | Caliber 3285 |
| Power reserve | About 70 hours | About 70 hours |
| Bezel insert | Aluminum, burgundy and blue | Ceramic, red and blue |
| Water resistance | 200 meters | 100 meters |
| Bracelet | Riveted-style steel, or a strap | Jubilee or Oyster |
| Date | Yes | Yes, with Cyclops lens |
How both watches work
A GMT watch shows a second time zone with an extra hand that circles the dial once every 24 hours and is read against the bezel. There are two ways to build one, and the difference matters to travelers.
On a true GMT, sometimes called a flyer's GMT, the ordinary hour hand can be moved forward or backward in one-hour jumps without stopping the watch. When you land, you pull the crown out one step and click the hour hand to local time; the 24-hour hand keeps showing home. Both of these watches work this way. Many less expensive GMT watches instead let you adjust the 24-hour hand, which suits people tracking another time zone from their desk.
That Tudor offers the same function as Rolex, in a movement made for Tudor, is the main reason the Black Bay GMT was such an event when it appeared in 2018. Our guide to the best GMT watches explains the two types.
The Tudor Black Bay GMT
The Black Bay GMT has a 41 mm steel case with the Black Bay's large crown and "snowflake" hands, including a red snowflake hand for the second time zone. Its bezel insert is anodized aluminum in matte burgundy and blue, which gives it the look of a watch from the 1950s and 1960s.
The movement, the MT5652, is a chronometer certified by COSC with a silicon balance spring and a power reserve of about 70 hours. The watch is water resistant to 200 meters, twice the Rolex's rating.
It comes with a black dial or, since 2023, an opaline white one, on a riveted-style steel bracelet, a leather strap or a fabric strap.
Two things to know before you buy. First, it is not a small watch: the case is noticeably thicker than the Rolex, and it sits tall on the wrist. Second, an aluminum bezel can fade and mark over many years, which some owners consider character and others do not.
Tudor has since added the Black Bay 58 GMT, a 39 mm watch with a Master Chronometer movement, for buyers who want the same function in a slimmer case.
The Rolex GMT-Master II
The GMT-Master is the original of the type, introduced in 1955 for airline pilots. The current steel model is 40 mm, about 12 mm thick, and wears flatter and lighter than the Tudor.
Its bezel insert is Cerachrom, Rolex's ceramic, in two colors made as a single piece. It does not fade and is very hard to scratch. The caliber 3285 is certified as a Superlative Chronometer, to within two seconds a day. The bracelet, Jubilee or Oyster, has solid links, a refined clasp and the Easylink extension of about 5 mm.
The steel GMT-Master II comes with several bezels, which we compare in Pepsi vs Batman vs Sprite.
What the extra money buys
- A ceramic bezel. It will look the same in twenty years. The Tudor's aluminum will age.
- A slimmer case. The Rolex is easier to wear under a cuff.
- Tighter accuracy. Rolex certifies to plus or minus two seconds a day; COSC allows a wider range, though Tudor's own standard is stricter than COSC requires.
- The bracelet and clasp. The Rolex bracelet is the better made of the two, with a quick extension.
- The name, and the resale market. The GMT-Master II is one of the most sought-after watches in the world, and it has held its value accordingly.
What the Tudor does better
- Price. It costs a fraction of the Rolex, new or pre-owned.
- Water resistance. 200 meters against 100.
- Availability. You can simply buy one.
- Wearing it without worry. Many owners find they wear the less expensive watch more freely, on trips and at the beach.
Which should you choose?
Choose the Black Bay GMT if you want a real traveler's GMT at an accessible price, like a vintage look, and have a wrist that suits a 41 mm watch with some height.
Choose the GMT-Master II if you want the original, value a slim case and a ceramic bezel, and are comfortable with the price.
They are not rivals so much as two rungs of the same ladder: Tudor is Rolex's sister company, and the Black Bay GMT was designed to offer the same idea for less. Our comparison of Tudor and Rolex explains the relationship.
What to check before you buy
- Size. Compare 41 mm and 40 mm, and above all the thickness. Our guide to choosing your watch size will help.
- Bracelet or strap on the Tudor: the bracelet version costs more.
- The bezel. On both it should turn in both directions with clear clicks.
- Box and papers. The warranty card shows the reference and the date of sale.
You can browse the Black Bay and GMT-Master II watches we have in stock, and read our guides to the Tudor Black Bay family and the GMT-Master II.
Frequently asked questions
Is the Tudor Black Bay GMT a true GMT?
Yes. Its local hour hand jumps in one-hour steps without stopping the watch, the same way the Rolex GMT-Master II works.
Is the Tudor Black Bay GMT bigger than the Rolex?
Yes. It is 41 mm against 40 mm, and it is thicker, so it sits taller on the wrist.
Does the Black Bay GMT have a ceramic bezel?
No. Its bezel insert is anodized aluminum. The Rolex GMT-Master II has a ceramic Cerachrom insert.
Which is more water resistant?
The Tudor, at 200 meters. The Rolex GMT-Master II is rated to 100 meters.
Does Rolex make the Tudor movement?
No. The MT5652 is made for Tudor by its own movement maker. Tudor and Rolex are sister companies, but the movements are different.
Is Watchflix NYC an official Tudor or Rolex retailer?
No. We are an independent retailer and are not affiliated with either brand. Every watch is checked by our specialist before it ships.
