
Tap the image to enlarge

Seiko Prospex Marinemaster 1968 Heritage Diver 42.6mm Mens Watch White
Ref. SLA077J1
Sits in Seiko’s upper tier here — more premium than three quarters of the Seiko watches we list, which start at £110.
Price range £110 to £3,550 across 186 Seiko watches in stock.Rooted in Seiko's 1968 professional diver, the SLA077J1 carries a 42.6mm stainless steel case with a super-hard coating, measuring 13.4mm thick across a lug-to-lug span of 49.3mm. The dual-curved sapphire crystal features an anti-reflective coating on its inner surface, and the screw-down crown sits at the four o'clock position. A unidirectional elapsed-timing bezel with a hard-coated insert completes the dive-ready exterior. The silvery white dial has a sand-like texture and carries LumiBrite on the hands, indices, and the twelve o'clock bezel marker. The date window falls between four and five o'clock. Inside, the hand-assembled calibre 8L35 runs at 28,800vph with a 50-hour power reserve and hacking seconds. The five-row bracelet shares the case's hard coating and fastens with a three-fold clasp incorporating a push-button release and diver's extension.
- Reference
- SLA077J1
- Brand
- Seiko
- Collection
- Prospex
- Case size
- 42.6mm
- Case thickness
- 13.4mm
- Lug width
- 20mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Silver
- Crystal
- Sapphire
- Bezel
- Unidirectional rotating
- Movement
- Automatic
- Calibre
- 8L35
- Functions
- Date
- Water resistance
- 300m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Three-fold clasp
- Lume
- LumiBrite
- Retailer
- Mappin & Webb
Additional specifications
- Lug-to-lug
- 49.3mm
- Power reserve
- 50 hours
- Weight
- 196g
Learn more about Seiko
Kintaro Hattori opened a watch and clock shop in Tokyo in 1881, aged twenty-one, and began manufacturing under the name Seikosha — roughly, house of exquisite workmanship — in 1892. The Seiko name appeared on watches from 1924.
The company's significance is that it broke the Swiss monopoly twice. First on precision: Seiko was appointed official timekeeper of the 1964 Tokyo Olympics and built the quartz chronometers and printing timers to do it, and in the 1960s its movements placed highly at the Neuchâtel and Geneva observatory trials against the best Swiss houses.
Then on technology. On Christmas Day 1969 Seiko released the Astron, the world's first quartz wristwatch, accurate to five seconds a month where mechanical watches managed that per day. The consequences for Switzerland were catastrophic — employment in the Swiss industry fell by roughly two-thirds over the following decade. Seiko deliberately did not enforce its quartz patents, allowing the technology to spread.
The same year it produced the 6139, among the first automatic chronographs, and it has since introduced Kinetic, Spring Drive — a hybrid regulating a mechanical mainspring electronically, giving a perfectly gliding seconds hand — and its own dive and field lines.
Seiko remains fully vertically integrated, making its own hairsprings, quartz crystals, and even the Zaratsu-polished cases, at price points from under a hundred pounds upward.
- 1881
- Kintaro Hattori opens his Tokyo shop.
- 1924
- The first watches carry the Seiko name.
- 1964
- Official timekeeper of the Tokyo Olympics.
- 1969
- The Astron becomes the first quartz wristwatch.
- 1999
- Spring Drive enters production.
Also in 7 collections
This watch appears in the Seiko Prospex range (32), Back in Stock (3,229), Stainless Steel Watches (3,088), Automatic Watches (1,763), Sports Watches (794), Silver Dial Watches (702) and Dive Watches (567).
Manufacturer’s guarantee
Best of 2 retailers
What the specifications mean
A mechanical watch built to be worn hard and got wet.
Strengths
- 300m water resistance, rated for actual diving
- 49.3mm lug-to-lug keeps the 42.6mm case wearable
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
- One of Seiko's more premium watches
Seiko Prospex Marinemaster 1968 Heritage alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | SLA077J1 | 821.10.101.10 | R32149318 |
|---|---|---|---|
| Price | £2,580 | £2,590 | £2,500 |
| Case size | 42.6mm | 42.5mm | 42mm |
| Water resistance | 300m | 300m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Stainless steel bracelet | Titanium bracelet |
| Power reserve | 50 hours | 38 hours | 80 hours |
| This watch | Closely matched | Closely matched |
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 300m it is rated for swimming, snorkelling and recreational diving.
Water resistance explainedWill the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Sapphire, mineral and acrylic comparedDoes it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
Quartz, automatic and solar comparedHow long does it run for when it's not worn?
About 50 hours fully wound — enough to survive a night off the wrist, but not a full weekend.
What size strap does it take?
20mm. Any strap of that width will fit, and on most modern watches quick-release bars make the swap a two-minute job with no tools.
Will it fit my wrist?
Lug-to-lug is 49.3mm, which suits wrists from roughly 16.5cm (6½ inches) upward.
Lug-to-lug decides fit more than case diameter does.
How to size a watch to your wristIs it a men's or women's watch?
Listed as men's.
Cheapest place to buy
Both Goldsmiths and Mappin & Webb list it at £2,580, so choose on delivery and warranty rather than price.
More Seiko watches like the Prospex Marinemaster 1968 Heritage
In stock, and close on style and price










