Side by side

Sinn 104 Classic 12vsSeiko Prospex Sea

The numbers, the dial colors, the calibers — laid out so you can stop flipping between tabs.

What people say

Owners + reviewers, side by side

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Sinn 104 Classic 12

The Sinn 104 Classic 12 is widely praised for its excellent legibility, comfortable wearability, and overall quality, with one owner deeming it the best watch under $3000 for their needs. Reviewers and owners alike highlight the bidirectional bezel action as a strong point, and the H-link bracelet is noted as sturdy and comfortable. However, one reviewer finds the handset and "Automatik" font slightly at odds with the dial, and another commenter describes Sinn watches as too thick with "plasticky" hands and an inner bezel edge that doesn't match promotional images. The watch is priced at €1,750, and its H-link bracelet lacks modern quick-release or micro-adjustment features. On balance, owners and reviewers rate the Sinn 104 Classic 12 highly for its pilot's tool functionality and value.

Seiko Prospex Sea

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.

At a glance

16 of 29 specs differ
Diameter
104 Classic 1241mm
Prospex Sea41mm
Power Reserve
104 Classic 1238h
Prospex Sea70h
Water Resistance
104 Classic 12200m
Prospex Sea200m
MSRP
104 Classic 12$2,203
Prospex Sea$900

Full specifications

Case

5 specs
Category
Tool
Diver
Thickness
11.9mm
12.3mm
Lug-to-Lug
46.9mm
Finish
polished
Caseback

Crystal & Dial

5 specs
Crystal Shape
Curved
AR Coating
Underside
Anti-reflective coating on inner surface
Dial Color
Black
Indices
Applied
Lume
Luminescent
LumiBrite on hands, index(es) and bezel

Movement

5 specs
Caliber
Sellita SW261-1
Seiko 6R35
Beat Rate
28,800 vph
0 vph
Power Reserve
38h
70h
Jewels
31
24
Complications
GMT
None

Pricing

1 specs
MSRP
$2,203
$900
Keep exploring

More watches worth a look

Matched to the watches above on size, movement, style and price — microbrands first. Open any one to dig in.

Follow this matchup

Get a note when Sinn 104 Classic 12 vs Seiko Prospex Sea gets more votes, a community discussion, or a price drop. No account needed.

Adjacent matchups

People also compared

Comparisons nearby in the catalog — alternatives to the watches above paired against the matchup.