Side by side

Bremont ionBirdvsSeiko Prospex Sea

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

ionBird
BremontionBird
MSRP $5,800
Prospex Sea
SeikoProspex Sea
MSRP $1,100

At a glance

14 of 29 specs differ
Diameter
ionBird43mm
Prospex Sea41.3mm
Power Reserve
ionBird40h
Prospex Sea72h
Water Resistance
ionBird
Prospex Sea300m
MSRP
ionBird$5,800
Prospex Sea$1,100

Full specifications

Case

7 specs
Category
Pilot
Diver
Diameter
43mm
41.3mm
Thickness
12.5mm
Lug-to-Lug
48.2mm
Lug Width
20mm
Material
Titanium
Stainless Steel
Water Resistance
300m

Crystal & Dial

3 specs
AR Coating
Inner
Anti-reflective coating on inner surface
Dial Color
Regular length (15cm - 19cm wrist size)
Black
Lume
None
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
6R55
Power Reserve
40h
72h
Jewels
25
24

Pricing

1 specs
MSRP
$5,800
$1,100

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What people say

Owners + reviewers, side by side

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

Bremont ionBird

Owners report the Bremont ionBird is overpriced and features a printed dial with a poorly placed date window at 4:30, which some find visually disruptive. However, some owners suggest its case finishing is superior to competitors. The 43mm titanium Bremont ionBird GMT is powered by a COSC-certified BE-93-2AV automatic movement and retails for $5,795. On balance, owners and reviewers find the Bremont ionBird's date window placement and price point to be significant drawbacks.

Seiko Prospex Sea

Seiko Prospex Sea models are widely praised for their excellent build quality, value for money, and comfortable wearability, with many appreciating the vintage-inspired designs and robust construction. Owners note the silicone straps are surprisingly comfortable and well-finished, and the Lumibrite lume is excellent. However, some find the 44.3mm size and thickness too large for smaller wrists, though others report the sizing as perfect. The 6R15 movement in some variants offers accuracy around +4 seconds per day with a 50-hour power reserve, while newer movements offer more. Some models are criticized for a bracelet width not matching the case size or a rudimentary clasp for their price point. Overall, owners and reviewers rate the Seiko Prospex Sea highly for its impressive case work and finishing at its price point.

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