Pilot and GMT Watches for Travellers: How Dual-Time Watches Work

A GMT watch answers one question without you having to do arithmetic: what time is it somewhere else? For anyone who crosses time zones, works with colleagues in another country, or simply wants to know whether it is a reasonable hour to call home, it is the single most useful complication after the date.

The category overlaps with pilot's watches, which is a matter of history rather than function. Aviation is where the need for two time zones first became routine, and the visual language of the pilot's watch — high-contrast dial, large numerals, rotating scales — grew out of the requirement to read an instrument quickly. This guide covers both, and explains how to actually use them.

How a GMT complication works

A true GMT watch has a fourth hand that completes one revolution every 24 hours, read against a 24-hour scale. Because it turns at half the speed of the hour hand, one position on the scale is unambiguous: it distinguishes 09:00 from 21:00, which a normal 12-hour hand cannot.

The 24-hour scale sits either on the bezel or printed on the dial. Both work. A bezel-mounted scale has an advantage worth understanding, which we come to below.

Tickmere's GMT watches are led by Seiko's Calibre 4R34, which puts a genuine 24-hour GMT hand into an automatic movement at a price that used to be impossible:

• The Seiko 5 Sports GMT SSK043K1 — 42.5mm × 13.6mm, rose gold sunburst dial, red GMT hand, bi-colour 24-hour bezel, Jubilee-style bracelet, approximately 41-hour reserve, 100 metres water resistance.
• The Seiko 5 Sports GMT SSK003K1 — the same 4R34 architecture with a blue sunburst dial and a bidirectional black-and-blue GMT bezel, 22mm steel bracelet, 100 metres.

Both also have hand-winding, hacking and a day-date display, inherited from the 4R family. See our entry-level automatics guide for how these sit against the rest of the range.

Caller versus flyer — the distinction that matters

There are two ways to build the complication, and they suit different people.

A "caller" GMT lets you jump the 24-hour hand independently, in one-hour steps, while local time keeps running. This is the right tool if you stay in one place and want to track another zone — a colleague in New York, family in Australia. You set it once and adjust only when daylight saving shifts.

A "flyer" GMT lets you jump the local hour hand independently, leaving the 24-hour hand as your unchanging home reference. This suits people who actually travel: land, jump the local hour hand to the new zone, and home time remains readable without touching anything else.

Neither is better in the abstract; they solve opposite problems. If you are buying specifically for travel, it is worth establishing which behaviour a given watch has.

Setting a GMT watch

The reliable method, whichever type you have:

Wind the watch, or wear it until it is running confidently.

Set the 24-hour hand to your home time, remembering it is a 24-hour scale — 3pm is at the 15 position, not the 3.

Set local time on the main hands.

Check the date rolls at midnight rather than midday. If it changes at noon, the hour hand is twelve hours out — advance it a full turn.

Avoid setting the date between roughly 9pm and 3am, when the date change mechanism is engaged. Forcing it then is a common cause of damage. More on this in the care guide.

The bezel trick: a third time zone

If the 24-hour scale is on a rotating bezel, you get something extra. Rotate the bezel by the offset between two zones and the GMT hand now reads a third zone against it — while the dial still shows local time and the fixed reference is preserved.

This is why the bezel-mounted 24-hour scale on the Seiko 5 Sports GMT models is more than styling. It is also why a bidirectional bezel is correct here, in contrast with dive watches where the bezel must be unidirectional for safety — see how to choose a dive watch for that distinction.

Pilot's watches: what the design is actually for

The pilot's watch idiom is about reading time under bad conditions — vibration, poor light, gloves, glancing rather than looking. The features follow from that: matte dials that do not reflect, oversized Arabic numerals, high-contrast luminous hands, and generously sized crowns.

Some genuinely aviation-derived functions:

Elapsed-time rings. The Bulova A-15 Pilot is a reissue of a 1944 military issue elapsed-time watch, and it keeps the original's two-crown arrangement: the crown at 2 o'clock rotates an inner disc for elapsed time, the crown at 4 o'clock a second disc indicating dual time. It runs a 21-jewel automatic with a 42-hour reserve under a sapphire crystal with anti-reflective coating. Note that it is rated to 30 metres — this is a watch to keep dry, despite the tool-watch appearance.

Chronographs and tachymeters. Timing was aviation's other requirement, which is why so many pilot's watches are chronographs. The Bulova Lunar Pilot is a 43.5mm chronograph based on the design of the Bulova chronograph worn on the moon on 2 August 1971. The current version uses Bulova's high-precision quartz movement running at 262 kHz, driving a 1/20th-second chronograph counter at 3 o'clock, running seconds at 6 and a 60-minute counter at 9, under a flat sapphire crystal with a tachymeter ring. It ships on a steel bracelet with an interchangeable leather NATO strap, both with an easy-release system. Our chronograph guide explains how to read the counters and the tachymeter.

Legibility above all. The TAG Heuer Autavia is a 42mm pilot-style watch with a smoky blue dial, Arabic numerals, white Super-LumiNova hands, a bidirectional polished ceramic bezel and 100 metres of water resistance, running a Swiss automatic Calibre 5 chronometer movement with a 38-hour reserve on a brown calfskin strap. It is ex-display stock — see what that means.

Simpler alternatives worth considering

You do not need a GMT hand to know the time elsewhere.

A world time quartz watch does the same job with a city ring and often more zones. The Casio Edifice EFV-100D is a 42mm quartz piece with a world time function and 100 metres of water resistance, at a fraction of the price of any mechanical GMT.

And for pure travel practicality, quartz has a real advantage: it is correct after three weeks in a suitcase, where a 41-hour automatic is not. The movements guide covers the trade-off.

Choosing

| Your situation | Sensible choice | |---|---| | Tracking one other zone from home | Caller GMT, or a world-time quartz | | Flying between zones regularly | Flyer GMT, so home time stays fixed | | Want a mechanical GMT at the lowest price | Seiko 5 Sports GMT, Calibre 4R34 | | Want a third zone from the bezel | GMT with a rotating 24-hour bezel | | Timing things, not tracking zones | A chronograph — see our guide | | Watch will sit unworn between trips | Quartz, every time |

Practical notes for travel

Take the watch off and put it in your hand luggage rather than checked baggage. Reset it to local time on landing, ideally out of the date-change window. If you wear it swimming on holiday, rinse it in fresh water afterwards — water resistance degrades faster in salt and sun cream than most people expect.

Browse Tickmere's GMT watches, pilot watches and chronographs.

Watch Insider is Tickmere’s editorial brand and newsletter. Subscribe from the homepage footer for new guides, or browse the full hub at Watch Insider.