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 $625

At a glance

14 of 29 specs differ
Diameter
ionBird43mm
Prospex Sea43.8mm
Power Reserve
ionBird40h
Prospex Sea41h
Water Resistance
ionBird
Prospex Sea200m
MSRP
ionBird$5,800
Prospex Sea$625

Full specifications

Case

7 specs
Category
Pilot
Diver
Diameter
43mm
43.8mm
Thickness
12.8mm
Lug-to-Lug
48.7mm
Lug Width
22mm
Material
Titanium
Stainless Steel
Water Resistance
200m

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
4R35
Power Reserve
40h
41h
Jewels
25
23

Pricing

1 specs
MSRP
$5,800
$625

Follow this matchup

Get a note when Bremont ionBird vs Seiko Prospex Sea gets more votes, a community discussion, or a price drop. No account needed.

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

The Seiko Prospex Sea is widely praised for its excellent value, solid build quality, and comfortable wearability, with many models featuring impressive lume and attractive dials. Owners and reviewers highlight the modern upgrades on classic designs, such as drilled lugs and reliable movements with hacking and hand-winding capabilities. Some models are noted for their refined case finishing and scratch resistance. Accuracy figures vary, with one owner reporting approximately 4 seconds fast per day, while others find the movements offer good performance for the price. Concerns raised by owners and reviewers include clasps that can feel generic or cheap, and lug widths that some find disproportionate to the case size on certain models. The thickness and weight of some Prospex Sea watches are also noted as substantial. The GMT function on specific models is considered secondary and difficult to read for true travel purposes.

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.

Adjacent matchups

People also compared

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