What is a GMT Watch?

Perfect for frequent travelers or those who have friends and family in far-flung places, a GMT watch keeps track of two time zones simultaneously. Local time is displayed via the traditional hour, minute, and seconds hand at the center of the dial while the second time zone is read via an additional hour hand that points to a 24-hour marked bezel. Clever in conception, easy to use, and often, superbly sporty in style, it’s not surprising that GMT watches are one of the most popular designs in the luxury watch landscape today. 

From their history to the different versions available, here’s everything you need to know about GMT watches. 

Brief History

In the 1950s, commercial airlines were flying further distances to transport tourists all over the globe, thus, crossing more time zones in a single day than ever before. As a result, pilots needed a way to track the local time in the city they were flying into, as well as their standard time (also known as reference time). To avoid any confusion, the aviation industry operates on a standard time. Today, this is known as Coordinated Universal Time (UTC) but back in the 1950s, it was called Greenwich Mean Time (GMT). 

The first GMT Watch

Pan Am Airlines reached out to Rolex to develop a watch to serve the needs of their fleet of pilots, and the Rolex GMT-Master was unveiled to the public in 1955. The design of the original Rolex GMT watch managed to solve the cockpit crew’s timing problem while also being exceedingly easy to use. The watch featured four hands on the dial – two hour hands, one minute hand, and one seconds hand – and a rotating blue and red bezel (now known as the “Pepsi” bezel) with a 24-hour scale. One hour hand made one full rotation every 12 hours while the other every 24 hours. Therefore, to set the second time zone, the wearer simply had to turn the bezel to align the 24-hour hand with the correct hour. 

It’s important to mention that the Glycine Airman debuted two years before the Rolex GMT-Master, technically the first watch to track two time zones. However, The Glycine Airman displayed both time zones on a 24-hour scale.

In the 1980s, Rolex introduced the GMT-Master II, which decoupled the pair of hour hands. Therefore, the second time zone could be set without having to rotate the bezel. Today, Rolex only makes GMT-Master II watches as it discontinued the GMT-Master I range in 1999. 

Although Rolex GMT-Master watches are the most famous since they popularized the complication, plenty of other watch brands now offer GMT watches too.

How Does a GMT Watch Work? 

Depending on the specific type, GMT watches work slightly differently in terms of how they’re set, adjusted, and used out in the wild. However, all GMT watches indicate two time zones at once – usually called home time and local time when you’re traveling. 

Local time is displayed via the traditional trio of hands – hour, minute, and seconds, read off the main dial. Home time (or reference time or alternate time) is displayed via a 24-hour hand (usually with a large arrow tip) that points to a 24-hour scale (either on the bezel or dial), along with the traditional minute and seconds hands. 

While the terms GMT watches and dual-time watches are sometimes used interchangeably, GMT watches are different because the second time zone is displayed on a 24-hour scale. On the other hand, dual-time watches display the second time zone on a 12-hour scale with a day/night indicator.

More from this series: 
What is a Chronograph Watch?
What is a Minute Repeater?
What is a Tourbillon?

Different Types of GMT Watches

The two main types of GMT watches are often referred to as Traveler and Caller. 

Traveler GMT / True GMT

A Traveler GMT (also known as a True GMT) watch includes an independent 12-hour hand. This makes it easy to change the local time zone when you’re traveling around the world. For instance, when you’re at home in New York, you can set both time zones to point to the same time. However, let’s say you fly to Hong Kong on business, you can quickly adjust the 12-hour local hand (without disturbing the other hands) as you land at the airport – and the second time zone will show you what time it is back in New York. 

True GMT watches are more complex to make, and therefore typically more expensive. Some of the most popular GMT watches include: 

• Rolex GMT-Master II
• Rolex Explorer II
• Tudor Black Bay GMT
• Tudor Black Bay Pro
• Omega Planet Ocean GMT
• Grand Seiko Evolution 9 Sports Spring Drive GMT
• Longines Spirit Zulu Time

Caller GMT/ Office GMT

A Caller GMT (also known as an Office GMT) watch includes an independent 24-hour hand. This makes it easy to set the second time zone and is particularly useful for those working across multiple time zones – hence its nicknames. For instance, if you’re based in New York but have offices in Hong Kong, you can quickly adjust the 24-hour hand (without disturbing the other hands) to show 13 hours ahead. 

Some of our favorite Caller GMT watches include: 

• Panerai Luminor GMT “Tuxedo Dial” PAM 29
• Breitling Chronomat GMT
• TAG Heuer Aquaracer Professional 300 GMT
• Oris Aquis GMT Date
• Zodiac Super Sea Wolf GMT
• Montblanc Heritage GMT
• Bell & Ross BR V2-93 GMT

Look at some of the best luxury watch brands in the world and you’ll see that many of them include at least one GMT model in their collections. If you’re looking for something different than Rolex’s iconic model, check out Marco Ferrante’s thoughts on the top 5 Rolex GMT-Master II alternatives. 

More from this series:
What is a Perpetual Calendar Watch? 
What is a Tourbillon Watch? 
What is a Dive Watch? 
What is a Minute Repeater Watch?
What is a Chronograph Watch?