Rolex GMT Master Guide (1)

Top 0.6%

In the 1950s, When the GMT Master was introduced, Only 0.6% of Americans traveled abroad in a year.
Even the most affordable tourist class round-trip ticket from New York to London cost about $486, Which exceeded 10% of the median annual household income in the US (about $4, 400).
Overseas travel was a privilege enjoyed by only a select few.

Pan Am international flight in-flight service
https://www.hope.ac.uk

For these 0.6% of travelers and the pilots responsible for their safe flights, It was important to keep track of the time at both the departure point (for example, New York) and the destination (for example, London) at the same time. The Rolex GMT Master was created specifically for them.

Rolex GMT Master advertisement introducing Pan Am's first nonstop New York–Moscow flight
https://www.analogshift.com

The blue-red "Pepsi" bezel, Devised by Rolex to distinguish between day and night, Later became the symbol and standard of GMT watch design and elevated the GMT Master to iconic status. Now, More than 70 years since its debut, The GMT Master has become one of the most actively traded "blue-chip" models in the pre-owned watch market. If you are considering purchasing a GMT Master or already own one and are curious about its story, Please read on.

"Please create a timepiece for the airline that rules the skies"

Rolex GMT Master advertisement 'Pan Am flies with Rolex'
https://www.sothebys.com

Pan American World Airways (hereafter "Pan Am") was the world's largest international airline at the time. As long-haul routes crossing multiple time zones increased, Pan Am determined that pilots needed a watch that could display both departure and destination times simultaneously and requested Rolex to create such a timepiece.

To meet Pan Am's requirements, Rolex developed an automatic movement in which the regular hour hand, Which completes one rotation every 12 hours, And a separate GMT hand, Which completes one rotation every 24 hours, Move in sync. They also added a 24-hour bezel to distinguish between day and night.

Bakelite bezel used in the first GMT Master (Ref. 6542)
https://le-monde-edmond.com

Rolex combined these two new elements with the design of the Oyster Perpetual models (Ref. 6202 Turn-O-Graph, Ref. 6204 Submariner), Which had previously introduced the rotating bezel, To complete the first GMT Master, Ref. 6542.

Rolex Turn-O-Graph Ref. 6202
https://www.europeanwatch.com

Submariner Ref. 6204
https://loupethis.com

GMT Master Ref. 6542
https://oliverandclarke.com

How to use a GMT watch

Let us assume you are on a business trip in New York and want to know the current time in Seoul. Of course, You could check with your smartphone, But this time let us use the GMT Master on your wrist.

Ref. 1675
https://www.windvintage.com

GMT stands for "Greenwich Mean Time, " which refers to the mean solar time at the Prime Meridian (longitude 0°) passing through the Royal Observatory in Greenwich, England. The standard time of each region in the world is indicated by the time difference from this reference (nowadays, Coordinated Universal Time, UTC, Based on atomic clocks), With negative (-) values to the west and positive (+) values to the east.

New York, About 5, 600 km west of London, Is GMT-4 (during daylight saving time), And Seoul, About 8, 900 km east, Is GMT+9. In other words, Seoul is 13 hours ahead of New York (14 hours during winter when daylight saving time ends).

First, Unscrew the crown and pull it out fully, Then set the hour hand, Minute hand, And GMT hand to point to 12 o'clock.

Next, Set the local time. If it is 9 a.m. in New York, Rotate the hour hand from the 12 o'clock position 270 degrees to point to 9 o'clock.

At this time, The GMT hand also moves, But at half the speed, So it moves exactly 135 degrees. The regular hour hand completes two rotations per day on the 12-hour dial, While the GMT hand completes one rotation per day on the 24-hour bezel.

Now it is time to rotate the bezel. Align the triangle marker on the bezel with the 12 o'clock position on the dial, Then rotate the bezel counterclockwise by 13 hours, Since Seoul is 13 hours ahead. The triangle marker will now be between 5 and 6 o'clock on the dial, And the GMT hand will point to "22" on the bezel. This means it is 10 p.m. in Seoul.

That completes the setting. Now, The hour and minute hands display the local time in New York (9 a.m.), While the GMT hand and 24-hour bezel simultaneously show the time in Seoul (10 p.m.).

TIP. For the GMT Master II (from Ref. 16760 released in 1982), If you unscrew the crown and pull it out to the first position, Only the hour hand moves independently in one-hour increments. The minute hand and GMT hand (home time) remain unchanged, And the date changes in sync with the hour hand. When you arrive at your destination, You only need to set the hour hand to the local time, So there is no need to stop the watch or reset the home time. This is the key feature that distinguishes the original GMT Master from the GMT Master II.

The most iconic color combination

Pepsi Cerachrom bezel insert
https://monochrome-watches.com

The design element that makes the GMT Master instantly recognizable is undoubtedly the rotating bezel. This two-tone bezel, Which divides the 24-hour scale into red (day) and blue (night), Has become the very identity of the GMT Master.

The combination of red, White, And blue, Completed by marking the numerals in white, Is reminiscent of the Stars and Stripes, And it is believed to have been especially well received in the United States, Which was the main market for the GMT Master at the time.

Red, White, And blue combination GMT Master II Ref. 126710BLRO
https://topwatch.com/

After the GMT Master, Several brands such as Seiko and Movado also adopted the blue-red bezel, Likely due to the symbolism of this color combination.

https://www.seikowatches.com

Movado Series 800 Pepsi bezel model
https://www.watch-connection.com

However, In April 2026, Rolex discontinued both the steel (Ref. 126710BLRO) and white gold (Ref. 126719BLRO) Pepsi models from its catalog to coincide with the opening of Watches and Wonders. While Rolex has not provided an official reason, Various interpretations have emerged, Ranging from the high production difficulty of the blue-red two-tone Cerachrom bezel to a generational change for a new colorway. What is certain is that you can no longer find a new Pepsi GMT at Rolex boutiques.

The discontinuation of the Pepsi bezel immediately impacted the pre-owned market. In Part 2, We will examine the market status of the GMT Master based on data, As well as the features of each reference from Ref. 6542 to 126710 and auction prices in 2026.

(To be continued in Part 2)