Side by side

Bremont Supermarine 300MvsSeiko Prospex Sea

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

Supermarine 300M
BremontSupermarine 300M
MSRP $3,550
Prospex Sea
SeikoProspex Sea
MSRP $595

At a glance

12 of 29 specs differ
Diameter
Supermarine 300M40mm
Prospex Sea41.7mm
Power Reserve
Supermarine 300M40h
Prospex Sea41h
Water Resistance
Supermarine 300M300m
Prospex Sea200m
MSRP
Supermarine 300M$3,550
Prospex Sea$595

Full specifications

Case

5 specs
Diameter
40mm
41.7mm
Thickness
12mm
12.3mm
Lug-to-Lug
49.5mm
Material
904L Stainless Steel
Stainless Steel
Water Resistance
300m
200m

Crystal & Dial

3 specs
Crystal
Sapphire
Hardlex
Dial Color
Green
Black
Lume
None
LumiBrite on hands, index(es) and bezel

Movement

3 specs
Caliber
BE-92AE
4R35
Power Reserve
40h
41h
Jewels
25
23

Pricing

1 specs
MSRP
$3,550
$595

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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 Supermarine 300M

The Bremont Supermarine 300M is praised for its comfortable 40mm and 42mm case sizes, with owners noting the 42mm wears well on smaller wrists due to its lug design. One owner highlights the 13mm thinness of the 40mm case, considered compact for a 300m diver. The watch is priced at $1375. On balance, owners and reviewers appreciate the Bremont Supermarine 300M for its wearability and compact dimensions, especially for a dive watch.

Seiko Prospex Sea

Owners and reviewers widely praise the Seiko Prospex Sea for its excellent value, robust build, and superior lume, with many noting its comfortable wearability and faithful design recreations. Some owners report the watch can feel big, thick, and heavy on smaller wrists, while others find the sizing perfect. The bezel action is frequently highlighted as smooth and precise, often exceeding that of less expensive models. On balance, owners and reviewers rate the Seiko Prospex Sea highly for its impressive finishing and value proposition.

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