How much does the Seiko Prospex Sea cost?

The Seiko Prospex Sea has a manufacturer MSRP of $900 USD. On the secondary market it averages around —.

What movement does the Seiko Prospex Sea use?

The Seiko Prospex Sea is powered by the 6R35 automatic movement with a 70-hour power reserve.

How big is the Seiko Prospex Sea?

The case measures 41mm in diameter, 12.3mm thick, with a 46.9mm lug-to-lug.

What is the water resistance of the Seiko Prospex Sea?

The Seiko Prospex Sea is rated to 200m of water resistance.

What kind of crystal does the Seiko Prospex Sea have?

The Seiko Prospex Sea uses a Sapphire crystal.

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Seiko Prospex Sea

Name: Seiko Prospex Sea
Brand: Seiko
SKU: spb317j1
Price: 900 USD
Availability: InStock

Ref. spb317j1

Diver

1 Variant

Lume:LumiBrite on hands, index(es) and bezel

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Retail MSRP

$900

Low

—

Avg

—

High

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Static data

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Open on eBay

Case

41mm

Power Reserve

70h

Movement

Automatic

Water Resistance

200m

Crystal

Sapphire + AR

Case Dimensions

Diameter41mm

Thickness12.3mm

Lug-to-Lug46.9mm

Lug Width20mm

Case Build

MaterialStainless Steel

Water Resistance200m

Crystal & Dial

CrystalSapphire

ShapeCurved

AR CoatingAnti-reflective coating on inner surface

LumeLumiBrite on hands, index(es) and bezel

Movement

Caliber

6R35

TypeAutomatic

Beat Rate—

Power Reserve70 hours

Jewels24

HackingNo

Hand-WindingNo

ComplicationsTime only

Design Language

Dial styleMatte

BezelRotating (dive)

Bracelet / strapRubber strap

HandsBaton

AI-detected from product image · 5/22/2026

In a nutshell

The Seiko Prospex Sea (ref. spb317j1) is an automatic diver watch, with a 41mm stainless steel case, 12.3mm thick, powered by the 6R35 movement and a 70-hour power reserve. Water resistance is rated to 200m, under a sapphire crystal. Manufacturer MSRP is $900.

Owners widely praise the Seiko Prospex Sea for its excellent lume, robust build, and value, with many highlighting the comfortable 4 o'clock crown and reliable movements. Reviewers note impressive case finishing and attractive dials, with specific models lauded for their gradient blue designs and smooth bezel actions. Accuracy figures vary, with one owner reporting +9 seconds/day after demagnetization, while others find the watches to be good first "proper" watches. Some owners find the stock rubber straps uncomfortable or the overall size substantial on smaller wrists. On balance, owners and reviewers rate the Seiko Prospex Sea highly for its combination of strong dive watch functionality and appealing design at its price point.