by Brent Robillard
Zulu Time or BB 58 GMT?
There is a point in almost every watch purchase when the shortlist gets very short. For anyone shopping for a Swiss GMT somewhere between entry-level luxury and the considerably more expensive offerings from brands like Rolex and Omega, two watches have become particularly difficult to ignore: the Longines Spirit Zulu Time and Tudor Black Bay 58 GMT.
The comparison is an obvious one. Both come from major Swiss brands with long histories. Both offer independently adjustable local-hour hands, chronometer-certified movements, rotating 24-hour bezels, strong bracelets, and case dimensions suited to everyday wear. Certain versions also occupy very similar territory at retail.
More importantly, both are very good watches.
That makes choosing between them considerably more interesting than declaring one the winner. After spending time with both, the differences have less to do with which watch is objectively better and more to do with what someone wants from a GMT.
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Two Different Takes on the Travel Watch
The Spirit Zulu Time joined the Longines collection in 2022, initially in a 42mm case. A smaller 39mm version followed and, for many wrists, immediately became the more compelling option.
Its design draws heavily from aviation. Large applied Arabic numerals dominate the dial, joined by the Spirit collection’s diamond-shaped hour markers and oversized crown. The bidirectional ceramic bezel provides the second 24-hour scale required to track a third time zone.
The Black Bay 58 GMT arrived in 2024 and takes a more familiar route. Tudor combined the compact proportions of the Black Bay 58 with a GMT complication, producing a 39mm travel watch that also addressed one of the biggest criticisms of the original 41mm Black Bay GMT: thickness.
At 12.8mm thick, the BB58 GMT is substantially slimmer than its older sibling and wears accordingly. The black-and-burgundy bezel, gilt details, Snowflake hands, and rivet-style bracelet leave little doubt that this is part of the Black Bay family.
The Tudor looks like a vintage-inspired tool watch that happens to have a GMT complication. The Longines looks more like a watch specifically designed around travel.
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Longines Spirit Zulu Time vs Tudor Black Bay 58 GMT: Size
On paper, there is surprisingly little separating them. The Tudor Black Bay 58 GMT measures 39mm across, 12.8mm thick, and approximately 47.8mm from lug to lug. The 39mm stainless steel Spirit Zulu Time measures roughly 13.5mm thick and 47mm from lug to lug.
The Longines is therefore slightly thicker, while its shorter lug-to-lug measurement helps compensate on the wrist. There is also a titanium Spirit Zulu Time measuring 39mm, giving buyers an option that feels noticeably lighter.
Both watches sit in something of a sweet spot for contemporary GMTs. Neither has the bulk associated with many travel watches, and both work well on wrists that might find a 41mm or 42mm GMT cumbersome.
The Tudor does have the edge in thickness. Its slab-sided case makes that 12.8mm measurement particularly important, and the BB58 GMT feels considerably more compact than the original Black Bay GMT.
The Longines counters with more sculpted casework and longer, narrower lugs. The result is a watch that feels slightly dressier and less overtly tool-like. This may be one comparison where trying both watches on is more useful than studying their dimensions.
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Two “flyer” GMT movements
Both watches use what enthusiasts commonly call a “flyer” or “traveller” GMT movement. The local hour hand can be adjusted independently without stopping the watch, making either model particularly convenient when arriving in a new time zone.
Inside the Spirit Zulu Time is the Longines calibre L844.4. Produced by ETA exclusively for Longines, the automatic movement operates at 25,200 vibrations per hour and provides approximately 72 hours of power reserve. It is also COSC certified.
The Tudor takes things a step further. Its manufacture calibre MT5450-U operates at 28,800 vibrations per hour, provides approximately 65 hours of power reserve, and carries METAS Master Chronometer certification.
METAS certification tests more than accuracy alone. It also includes resistance to magnetic fields up to 15,000 gauss, power reserve, water resistance, and performance in multiple positions and at different states of wind.
For someone buying largely on technical specifications, the Tudor has the stronger résumé. But not by much. In everyday use, the difference is less dramatic. The Longines still provides an excellent chronometer-certified GMT movement and actually offers slightly more power reserve.
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Where Tudor Pulls Ahead
The Black Bay 58 GMT’s greatest advantages become apparent when it is treated as an everyday sports watch rather than purely as a GMT.
Water resistance is rated to 200 metres compared with 100 metres for the Longines. Few owners are likely to test either figure, but Tudor provides considerably more reassurance for swimming and regular use around water.
Then there is the bracelet. Tudor’s T-fit clasp remains one of the better systems available in this segment. It allows quick tool-free adjustment and feels appropriately robust for a watch with the Black Bay’s tool-watch character. The faux rivets along the bracelet remain divisive, but the clasp itself is difficult to fault.
This is one area where the Spirit Zulu Time trails its competitor. Longines has made considerable improvements to its bracelets in recent years, but its clasp lacks the same degree of adjustment and refinement found on the Tudor.
Where the Longines Has an Advantage
Choice. Longines has developed the Spirit Zulu Time into a collection rather than a single GMT. There are multiple dial and bezel combinations, steel and titanium cases, bracelets and straps, and even two-tone executions. Buyers can choose between 39mm and 42mm cases as well.
The Tudor Black Bay 58 GMT is a much more tightly defined proposition. That can be an advantage if the Tudor’s particular combination of black, burgundy, and gilt appeals to you. If it doesn’t, there are considerably fewer places to go.
The Spirit Zulu Time also has a character distinct from Longines’ other major sports-watch collections. It doesn’t look like a HydroConquest with another hand added to the dial. The Arabic numerals, diamond-shaped markers, five stars, and aviation-inspired case give it its own identity.
It also transitions particularly well away from the bracelet. On leather, the Zulu Time can look surprisingly dressy for a 100-metre GMT.
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The Criticisms
Neither watch escapes criticism. For the Tudor, much of it centres on familiarity.
The Black Bay design has been enormously successful, but Tudor has also used its Snowflake hands, gilt accents, vintage-inspired cases, and rivet-style bracelets extensively. For collectors who already own another Black Bay, the BB58 GMT may feel very familiar.
The colour scheme is equally specific. Its burgundy-and-black bezel and gilt dial details give the watch considerable warmth, but anyone interested a blue-and-red “Pepsi” treatment or a cooler, more contemporary execution will have to keep waiting.
The faux rivets are another recurring complaint. They do nothing mechanically and remain one of Tudor’s most debated design choices.
The Longines has different weaknesses.
Its bracelet and clasp aren’t as accomplished as Tudor’s, and 100 metres of water resistance looks relatively modest beside the Black Bay’s 200 metres.
There is also a lot happening on the dial. Large Arabic numerals, five stars, multiple lines of text, a date window, and a fourth hand make the Zulu Time considerably busier than the Tudor. Some will find it rich in detail. Others may prefer the comparatively straightforward Black Bay.
And although the L844.4 is an excellent movement, Tudor’s METAS-certified MT5450-U provides the more impressive technical specification.
So, Who Is the Longines Spirit Zulu Time For?
The Longines makes the stronger argument for someone who wants a GMT first and a sports watch second.
Its design is more closely associated with aviation and travel, and the collection offers considerably greater variety. The 39mm models provide compact dimensions, while titanium gives buyers another option for reducing weight.
There is also a refinement to the Spirit Zulu Time that the Tudor doesn’t attempt to replicate. Put it on leather, and it can work surprisingly well with more formal clothing. Put it back on its bracelet, and it becomes a capable everyday sports watch.
For someone who already owns a dive watch or another Black Bay, the Longines may also add greater variety to a collection.
Who Is the Tudor Black Bay 58 GMT For?
The Tudor makes considerable sense for someone who wants one mechanical watch to cover almost everything.
Its 39mm case is compact, its 200 metres of water resistance provide genuine sports-watch credentials, the bracelet and T-fit clasp are excellent, and the METAS-certified movement is difficult to argue against.
It is the more overtly rugged watch of the pair.
There is also the strength of the Black Bay design itself. Tudor’s vintage-inspired aesthetic has become familiar for a reason. The large luminous markers, Snowflake hands, and uncomplicated dial remain exceptionally legible.
If your idea of a GMT is essentially a dive-style sports watch capable of tracking another time zone, the Tudor is probably the more natural choice.
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Longines Spirit Zulu Time or Tudor Black Bay 58 GMT?
This is where a conventional comparison would normally declare a winner. There really doesn’t need to be one.
The specifications favour Tudor in several important areas. The Black Bay 58 GMT is thinner, offers twice the water resistance, has the better clasp, and carries METAS Master Chronometer certification.
The Spirit Zulu Time responds with a longer power reserve, numerous configurations, a distinctive aviation-inspired design, and a character that can move more easily between sports watch and travel watch.
More importantly, they feel different on the wrist. The Tudor Black Bay 58 GMT feels like a compact tool watch with an excellent GMT complication. The Longines Spirit Zulu Time feels like a travel watch that happens to be tough enough for everyday use.
For someone choosing between them, that distinction may matter considerably more than 100 metres of additional water resistance or seven hours of extra power reserve.
And if the decision is still difficult, there is another Longines GMT that complicates matters further…
The HydroConquest GMT might deserve its own comparison. Hmm.
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About the author
Brent Robillard is a writer, educator, craftsman, and watch enthusiast. He is the author of four novels. You can follow him on Instagram.
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