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If you want the look and naval story of a military Rolex Submariner without buying a vintage example, CWC is the only one of the four brands here with a documented direct succession claim. CWC says its 1980 Royal Navy diver replaced the Rolex MilSub. Seiko, Marathon and Omega make capable diver watches, but the sources consulted support them as current diver watches with heritage or service identities, not as watches issued to a unit.
What “MilSub” should mean in this comparison
“MilSub” is shorthand for a military-issued Rolex Submariner, and the word is about issue history. This article uses “attainable” more loosely, to cover three different things: a watch with a documented successor claim, a watch with a heritage or purpose-built identity, and a civilian luxury diver in the same functional family. Keep those three claims separate whenever you read a product page.
- Historic military issue: the watch was supplied to a service during a defined period.
- Military contract or reissue: the maker won a government order, or recreates an earlier issued design.
- Civilian retail product: a current catalogue watch that may share a name, colourway or design cues with a military watch, but has no individual issue history.
How the four watches compare on provenance
| Brand and model | Type of claim | What the consulted sources support | What is not established |
|---|---|---|---|
| CWC RN Quartz Diver Mk.2 | Successor lineage; current product | CWC says its 1980 Royal Navy diver replaced the Rolex MilSub. The Mk.2 is a modern product in that line. | That a current Mk.2 was ever issued to a unit |
| Seiko Prospex Marinemaster 1968 Heritage Diver | Heritage-styled civilian diver | Marinemaster is Seiko’s flagship diver series. Seiko’s company history dates its first diver watch to 1965. | Any military issue for the listed model |
| Marathon GSAR | Purpose-built, service-oriented diver | Listed as the Official USMC Large Diver’s Automatic GSAR in Marathon’s Search and Rescue Dive series | Issue history of an individual retail watch |
| Omega Seamaster Diver 300M Milano-Cortina 2026 | Luxury civilian diver, special edition | Omega’s Japanese product page lists a 43.5 mm case, white ceramic and grade 5 titanium construction, and a Master Chronometer movement. | Military issue of this edition. The Royal Navy’s Omega link is only a broad 1960s lead. |
CWC: the only direct historical thread
What CWC claims about 1980
CWC’s company history says that in 1980 the firm won the contract for the Royal Navy divers’ watch that replaced the Rolex MilSub. The same history calls the 1980 Royal Navy Diver Automatic probably the rarest MilSub to date. That rarity claim is CWC’s own characterization, not an independently counted figure, so attribute it to CWC.
The 1980 design, as CWC describes it
CWC’s 1980 reissue page says the Royal Navy had earlier worked with Rolex and Omega, and that the CWC watch was built to the MOD specification DEF STAN 66-4 Part 1 Issue 3. The described design includes:
#1 Best Overall
- ❤Tik_Tok Hot Recommended: Fashionable sporty dial design, military style outlook. Large Dial (acrylic crystal glass window,case diamete High quality watch band,Reinforced resin band design is more ergonomic, comfortable to wear.), who like large dial watch should love this fashion sport watch. Fit for large wrists, and adjustments for different wrist sizes.
- ❤Multifunction: 1. Analog and digital dual dial support two different timezone 2. Alarm 3. LED Back Light(show time clear in the dark ) 4. Date 5. Stop Watch 6. 12/24H format option 7. Shock Resistant 8. Light Weight .Those funktions make it perfect for all kind of sport and daily use
- ❤Imported Japan quartz movement, keep precise time.Comfort with FASHION: soft and durable PU watch band with the large dual dial design make it comfortable to wear and lead you to edge sport fashion. Perfect for both indoor and outdoor activities, such as running, climbing, ect
- ❤Water resistant up to 5 ATM: Suitable for everyday use. Splash/rain resistant. Please don't press any buttons underwater, and in case of damaging waterproof ring,please keep it away from steam and hot water
- ❤Perfect after-sale, any question please do not hesitate to contact us. We will try our best to make customers satisfied.
- a rotating bezel with a fully hashed luminous insert
- sword hands
- tritium lume on the historical design
- a 32 mm mineral glass crystal (a crystal size, not the case diameter)
- fixed strap bars for pull-through nylon straps
These details describe the 1980 design. They do not automatically apply to every current CWC. The same page makes the case for the category in one line, which CWC attributes to its own reissue page: “The appeal of a Rolex MilSub is that it is essentially a watch from a large luxury brand customized to the specifications of a military unit for a unique purpose.”
The current RN Quartz Diver Mk.2
CWC’s current RN Quartz Diver Mk.2 product page presents a modern evolution of that design, with sapphire crystal and contemporary luminous materials. The contrast is useful: mineral glass and tritium on the period design, sapphire and modern lume on the current watch. The product page consulted does not give a complete specification set, so confirm case dimensions, movement, water resistance, price and stock on the live listing before buying.
Rank #2
- ❤Tik_Tok Hot Recommended: Fashionable sporty dial design, military style outlook. Large Dial (acrylic crystal glass window,case diamete High quality watch band,Reinforced resin band design is more ergonomic, comfortable to wear.), who like large dial watch should love this fashion sport watch. Fit for large wrists, and adjustments for different wrist sizes.
- ❤Multifunction: 1. Analog and digital dual dial support two different timezone 2. Alarm 3. LED Back Light(show time clear in the dark ) 4. Date 5. Stop Watch 6. 12/24H format option 7. Shock Resistant 8. Light Weight .Those funktions make it perfect for all kind of sport and daily use
- ❤Imported Japan quartz movement, keep precise time.Comfort with FASHION: soft and durable PU watch band with the large dual dial design make it comfortable to wear and lead you to edge sport fashion. Perfect for both indoor and outdoor activities, such as running, climbing, ect
- ❤Water resistant up to 5 ATM: Suitable for everyday use. Splash/rain resistant. Please don't press any buttons underwater, and in case of damaging waterproof ring,please keep it away from steam and hot water
- ❤Perfect after-sale, any question please do not hesitate to contact us. We will try our best to make customers satisfied.
Seiko: a heritage diver at a premium price
Seiko’s U.S. Marinemaster page calls the line the brand’s flagship diver series and lists a Marinemaster 1968 Heritage Diver’s Watch at USD 3,600. That price was observed when the page was retrieved in 2026. It is a retailer-page figure for that date and region, not a guaranteed current price, and it may have changed. The page supports Seiko’s diver heritage and a premium Seiko comparison. It does not support describing the listed Marinemaster as a military-issued watch.
Marathon: a purpose-built diver with a service identity
Marathon’s product page lists the Official USMC Large Diver’s Automatic GSAR, with a stainless-steel bracelet, in its Search and Rescue Dive series. The page states a two-year international warranty effective from purchase from an authorized dealer. Check the live listing for current warranty terms and the exact configuration you are considering. The GSAR’s service identity is what Marathon states on its product page; it does not mean that every retail example has a documented issue history.
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Rank #3
- Precision Timekeeping: Powered by a VH31 sweep seconds quartz movement, the men watches offers accurate and reliable timekeeping, ensuring you're always on time.
- Sapphire Crystal: The watch face is protected by a scratch-resistant sapphire crystal with AR coating, ensuring long-lasting clarity and a polished look even with regular use.
- Water Resistance: Water-resistant up to 100 meters (330 feet), this timepiece is can meet daily waterproof,such as washing hands, rain, swimming(please tighten the crown when going into the water). It is not recommended to wear the watch while diving or taking a hot shower.
- Luminous Hands and Markers: The quartz watch features BGW9 blue luminous hands and markers, ensuring easy readability even in low-light conditions, perfect for nighttime or dim environments.
- Comfortable Fit: The dive watches comes with a black nylon strap, it is lightweight and soft, with excellent breathability for all-day wear. There are multiple adjustment holes to fit most wrist sizes.
Omega: a luxury benchmark kept separate from military history
Omega’s Japanese product page for the Seamaster Diver 300M Milano-Cortina 2026 edition lists a 43.5 mm case, white ceramic and grade 5 titanium construction, and a Master Chronometer movement. It is a credible contemporary luxury diver for comparison. Its prices are yen figures for that Japanese page and should not be treated as a general current price without checking the market and currency. The page does not show that this special edition was a military-issued MilSub. The CWC history’s mention of Omega and the Royal Navy in the 1960s is a broad historical lead and does not establish a link to this model.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Specifications to check before comparing prices
The consulted pages do not give a normalised specification set for all four watches, so compare exact references using the manufacturer’s current data. Check these points for each one:
Rank #4
- WATCH SIZE: Case Diameter: 50mm / 1.97in, Case Thickness: 16mm / 0.63in, Band Length: 265mm / 10.4in, can suit circumference 140-220mm / 5.5-8.67in wrist to wear, Band width: 24mmm / 0.94in.
- Sports watch: Suitable for men, especially to those who like doing sports, multi-functions make it perfect for both outdoor and indoor sports, such as running, climbing, fishing and so on
- Waterproof to 50M / 164FT. In general, suitable for Swimming and cold shower,not suitable for long time underwater activities such as diving.
- Multi-functions watch: 1/100 second digital stopwatch, auto calendar, hourly alarm and alarm clock, shock resistant, 12/24 hour formats.
- High quality watch: Senior PU band, comfortable to wear. The dial window is made of acrylic mirror, high transparency, compressive and abrasion. This watch can meet your daily life, work, and sports needs.
- street price, the retailer, the country and the date of the price
- case diameter and thickness
- water-resistance rating
- movement type and, for automatics, power reserve
- bezel action and timing scale
- lume type and coverage
- strap or bracelet fit and attachment type
- service options and warranty terms
- documented issue evidence, if any
| Model | Case size | Movement | Water resistance |
|---|---|---|---|
| CWC RN Quartz Diver Mk.2 | Not stated on the consulted CWC product page | Quartz, per the model name | Not stated on the consulted CWC product page |
| Seiko Marinemaster 1968 Heritage Diver | Not stated on the consulted Seiko U.S. page | Not stated on the consulted Seiko U.S. page | Not stated on the consulted Seiko U.S. page |
| Marathon GSAR | Not stated on the consulted Marathon page | Automatic, per the model name | Not stated on the consulted Marathon page |
| Omega Seamaster Diver 300M Milano-Cortina 2026 | 43.5 mm (Omega Japan page) | Master Chronometer (Omega Japan page) | Not stated on the consulted Omega Japan page |
Strap compatibility
If you want the historical CWC look, check the attachment before you buy a strap. The 1980 design uses fixed strap bars for pull-through nylon straps. A standard two-piece strap will not fit that arrangement, so confirm the attachment type for the exact reference first.
Quick Recap
Which watch fits which goal
- If the naval lineage is the point: the CWC RN Quartz Diver Mk.2 is the only one of the four with a successor claim from the maker. Read that claim as CWC’s account of its own history, and treat the current watch as a modern product in that line.
- If you want a premium Japanese heritage diver: the Seiko Marinemaster 1968 Heritage Diver offers diver heritage and a flagship-series position, without a military-issue claim.
- If you want a purpose-built service identity: the Marathon GSAR fits, with the bracelet and warranty terms confirmed on the live listing.
- If you want a luxury benchmark and do not need military provenance: the Omega Seamaster Diver 300M is the most expensive comparison here, and its Japanese-page price needs checking in your own market.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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