HISTORY OF THE BENTHOS 500
2023: THE NEW ERA OF THE BENTHOS HAS BEGUN
1970: The beginning
History of Benthos 500
In 1970 Aquastar released what was to become one of the most iconic dive watches ever: the Benthos 500. The first non monobloc cased dive watch to be designed to operate at 500 meters depth, the Benthos 500 incorporated an innovative 60 minute flyback totalizer for timing a dive. Building on the trend of that era to make dive watches bigger and more substantial, the 500 measured in at: 47mm lug to lug, 42mm wide (48mm if you measure across the offset crown), 16mm high with a 4mm thick crystal and had a 20mm lug width. It also incorporated a 60 click bezel which was large and easy to grip even with gloved fingers and a simple high contrast dial. The Benthos 500 became a favorite of Jacques Mayol and he wore it when he broke the 100 meters freediving barrier with a no limits record dive to 101 meters in 1976. The watch would also be included in the approved equipment section of the 1973 US Navy Air Diving manual. A detailed retrospective of the Benthos 500 can be found here:
1987: 3300 Feet deep
1978 BENTHOS I
The 1970s could be classed as the depth ‘arms race’ in the dive watch world. There were serious bragging rights to be attained for having a deeper depth rating than the competitors and Aquastar stepped up their game to participate. The Benthos I was introduced and the depth rating doubled to 1,000 meters. The new watch looked visually similar to the Benthos 500 initially but looking close shows that there were a number of changes. The most substantial change was the caseback, or the lack of one. The Benthos I used a one piece monobloc case. This now meant that there were only two water ingress points. The crown, which was screwdown with double o-rings and the 4mm crystal, which had a screw down gasket compression ring. Overall, the case and bezel had rounded edges giving it a more streamlined look, but the biggest change was the clockwise rotation of the crown and totalizer monopusher by approximately 25 degrees so that the crown was now at a more traditional 3 o’clock position. The same Benthos 500 functionality was there but at double the depth.
1985: The Quartz ERA
1985 Benthos II Marine Nationale
When the Benthos II was released there had been a number of changes both at Aquastar and in the watch world. Frédéric Robert was leading a design team at another Swiss brand and the quartz revolution had begun to decimate mechanical Swiss watchmaking. With the Benthos II, Aquastar simplified the functionality of the watch. While the case was similar to the monobloc Benthos I, the movement was now a simple 3 hand quartz version, without the functionality of a totalizer and the need for a monopusher. The dial changed to show large luminous numbers and a smaller 24 hour count. The handset also changed. The Benthos II was still a 1,000 meter dive watch but simplified from the Benthos 500 and Benthos I. The Benthos II may have been a less complex watch to the two previous generations but it was highly thought of by the French Navy as several watches were issued to the French Navy “Marine Nationale”.
2023: THE RE-EDITION
2023, A NEW era has begun..
Retaining the original proportions and exact dimensions of the 1970 Benthos 500, the new 2023 Benthos H1 is built around a tonneau-shaped 42mm 904L stainless steel case, with the crown once again in its unique position at 2:00. As the purest expression of the Benthos visual DNA, this reference is powered by a Swiss-made genuine ETA 2824-2 Elabore grade movement, and has been embellished with modern updates throughout, including a unidirectional rotating dive bezel with a ceramic insert, and generously applied modern SuperLuminova in Aquastar’s signature “old radium” ecru color to punctuate its inky black dial. And just like the original Benthos with its pioneering depth resistance, the H1 also maintains a robust 500 meters of water resistance, making it once again, the deepest diving modern Aquastar to date.
Great divers / Great dive watches
The Benthos 500 MKII from 1974
1974 Benthos 500 Blue print
This is the blue print of the 1974 Benthos 500, made by Piquerez, the Swiss manufacturer of dive watch cases, that was the supplier for all high end Swiss watch brands in the 60s and 70s
Benthos 500 original hand drawing from 1968
long before the computers and CAD era, it was the painstaking work carried by a watch designer or engineer, to create a hand drawn model as close as possible to the real watch. Here is an example of a hand drawn Benthos 500 model from 1968.
Aquastar Benthos 500 II Founder’s Edition
The Archive
Benthos history, in photographs.
18 vintage Benthos photographs from the Aquastar private archive.
Frequently asked
Benthos history questions.
When was the Aquastar Benthos 500 released?
The Aquastar Benthos 500 was released in 1970 as the first Swiss dive-watch case rated to 500 meters of water resistance without a monobloc construction. It used a screwed case back with a new dual-gasket pattern (patented 1965 by Frederic Robert, CH 15 601/65) that meant the case could go to 500 meters and still be opened and resealed for service, unlike the sealed monobloc alternatives of the era. Listed in the U.S. Navy diving manual the year it launched.
Was the Benthos issued to the French Navy?
Yes. The third generation of the Aquastar Benthos was issued to French Marine Nationale combat divers based in Toulon from 1979 to 1984, approximately 3,200 pieces over the six-year procurement contract. The Marine Nationale specified the Aquastar over quartz alternatives because the mechanical bezel worked as a backup timing instrument even after a computer failure. The modern Benthos family is built on the same case architecture as the issued piece.
What made the Benthos able to reach 500 meters?
Three engineering decisions. Frederic Robert's 1965 dual-gasket waterproof crown (CH 15 601/65) sealed the most vulnerable point on the case at depth. A screwed case back with a specific 1970 gasket pattern replaced the monobloc approach, which allowed servicing. And the case profile was thicker at the crystal seat to resist crystal deformation under pressure. Rated to 500 meters, tested at 500 meters, opened and resealed at the workshop like any other Aquastar.
How many original Aquastar Benthos watches were made?
Original 1970s Benthos production was in the low thousands per generation, with the Marine Nationale third-generation contract of about 3,200 pieces representing the largest single batch. Total pre-1984 vintage Benthos production is estimated between 6,000 and 10,000 pieces across all generations. The modern re-edition family (Heritage II, Heritage One, Professional, 500 II) has been in continuous production in Bienne since 2024.
Can a vintage Benthos still be serviced?
Yes. The Bienne workshop still uses the 1970 Benthos gasket pattern in current production, so a fifty-year-old Benthos case can be opened, resealed, movement serviced, and pressure-tested with the same parts a new Benthos uses. Service interval is 5 to 10 years for a working piece even with regular diving. The workshop authenticates by serial number.
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