Side by side

Seiko Prospex Sea The Black SeriesvsSinn U18

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.

Seiko Prospex Sea The Black Series

The Seiko Prospex Sea The Black Series is widely praised for its impressive value and compelling design elements. Reviewers highlight the SLA073's cave-diving-inspired dial, high-quality bracelet, and the robust 8L35 movement, calling it a standout release. The SRPE33 and SRPE39 models are noted for their attractive price, manta ray decorated dials, and excellent LumiBrite lume, though bezel alignment can be inconsistent. The SNJ029 is celebrated for its dynamic, colorful aesthetic, solar charging, and comfortable strap, making it ideal for outdoor adventures. Overall, the consensus is that Seiko Prospex Sea The Black Series models offer excellent value, with specific models lauded for their unique dials, quality finishing, and practical features like solar charging.

Sinn U18

The Sinn U18 is praised for its unique deep blue/green dial with three-dimensional oxygen bubbles that change with light, and its comfortable, easily adjustable bracelet. Owners find the watch stunning and a piece of history, appreciating the refined hands. The Sinn U18 features a 44mm, 15.5mm thick case made from German submarine steel, offering a 2000-meter dive specification and Sinn's Ar-Dehumidifying technology, powered by a Sellita SW300-1 movement. The case thickness is apparent, and the watch comes as a complete set with box and papers for $3,000-$3,680. On balance, owners and reviewers rate the Sinn U18 highly for its striking dial and robust build.

At a glance

17 of 29 specs differ
Diameter
Prospex Sea The Black Series45mm
U1844mm
Power Reserve
Prospex Sea The Black Series41h
U1842h
Water Resistance
Prospex Sea The Black Series200m
U182,000m
MSRP
Prospex Sea The Black Series$765
U18$3,488

Full specifications

Case

7 specs
Diameter
45mm
44mm
Thickness
13.2mm
15.5mm
Lug-to-Lug
47.7mm
Material
Stainless Steel
high-strength
Finish
Water Resistance
200m
2000m
Caseback

Crystal & Dial

5 specs
Crystal Shape
AR Coating
Anti-reflective coating on inner surface
Dial Color
Black
Indices
Lume
LumiBrite on hands, index(es) and bezel
None

Movement

4 specs
Caliber
4R36
Sellita SW300-1
Beat Rate
0 vph
28,800 vph
Power Reserve
41h
42h
Jewels
24
25

Pricing

1 specs
MSRP
$765
$3,488
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 Seiko Prospex Sea The Black Series vs Sinn U18 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.