Kensington Watches
Seiko Alpinest 38mm Mens Watch Green

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Seiko

Seiko Alpinest 38mm Mens Watch Green

Ref. SPB155J1

Among our 166 Seiko watchesThis watch£670
Premium

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 £2,900 across 166 Seiko watches in stock.

At 38mm across and 12.9mm thick, with a lug-to-lug span of 46mm, this sits compactly on the wrist despite its substantial 148-gram stainless steel construction. The textured dark forest green dial carries a fumé gradient finish, with gold cathedral hands and a red-tipped seconds hand. LumiBrite coats both hands and hour markers. The date sits at three o'clock, and a power reserve indicator completes the dial layout. The curved sapphire crystal has an anti-reflective coating on its inner surface, and the exhibition caseback is also sapphire. Inside, the 6R35 automatic runs at 21,600vph with a 70-hour power reserve and hacking seconds. A screw-down crown and 200-metre water resistance round out a capable, neatly proportioned package on a three-fold clasp bracelet.

Reference
SPB155J1
Brand
Seiko
Collection
Prospex
Case size
38mm
Case thickness
12.9mm
Lug width
20mm
Case material
Stainless steel
Case shape
Round
Dial
Green
Crystal
Sapphire
Movement
Automatic
Calibre
6R35
Functions
Date
Water resistance
200m
Bracelet / strap
Stainless steel bracelet
Strap colour
Silver
Clasp
Three-fold clasp
Lume
LumiBrite
Retailer
Mappin & Webb
Additional specifications
Lug-to-lug
46mm
Power reserve
70 hours
Weight
148g
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.

All Seiko watches

Also in 7 collections

This watch appears in the Seiko Prospex range (32), Back in Stock (3,434), Stainless Steel Watches (2,782), Automatic Watches (1,540), Sports Watches (700), Dive Watches (503) and Green Dial Watches (396).

Manufacturer’s guarantee

Best of 3 retailers

What the specifications mean

A mechanical watch built to be worn hard and got wet.

Strengths

  • 200m water resistance, rated for actual diving
  • 38mm suits most wrists
  • Sapphire crystal, which resists scratching
  • 70-hour reserve survives a weekend off the wrist
  • Luminous hands and markers for low light
Best forDivingSwimmingEveryday wear

Price history

This watch is currently at its highest recorded price. It was £650 on 10 August. Prices are checked every day, and we record any changes.

£670£67010 August

Seiko Alpinest alternatives

Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.

Alpinest 38mm Mens Watch Green compared with 2 alternatives from other brands
SpecificationThis watchAlpinest 38mm Mens Watch GreenSPB155J1CertinaDS Action Day-Date Powermatic 80 41mm Mens WatchC0324301604100TissotPRS516 Powermatic 80 38mm Mens Watch BlackT1494071105100
Price£670£695£675
Case size38mm41mm38mm
Water resistance200m200m100m
MovementAutomaticAutomaticAutomatic
StrapStainless steel braceletLeather strapStainless steel bracelet
Power reserve70 hours80 hours
This watch
  • Wears larger
  • Rated shallower

Your new watch

Frequently asked questions, and things you should know about this watch

Can I swim with it?

Yes. At 200m it is rated for swimming, snorkelling and recreational diving.

Water resistance explained

Will the glass scratch?

Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.

Sapphire, mineral and acrylic compared

Does 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 compared

How long does it run for when it's not worn?

About 70 hours fully wound — enough to sit off the wrist over a weekend and still be running.

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 46mm, which suits wrists from roughly 16cm (6¼ inches) upward.

Lug-to-lug decides fit more than case diameter does.

How to size a watch to your wrist

Is it a men's or women's watch?

Listed as men's, though at 38mm it sits in the range that suits anyone.

Cheapest place to buy

All 3 UK retailers we track list it at £670.

Has the price changed recently?

It's currently at its highest recorded price. It's ranged between £650 and £670, today it's £670.

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