Side by side

Fortis Marinemaster M-40vsSeiko Prospex Sea

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

Marinemaster M-40
FortisMarinemaster M-40
MSRP $3,520
Prospex Sea
SeikoProspex Sea
MSRP $595

At a glance

12 of 29 specs differ
Diameter
Marinemaster M-4040mm
Prospex Sea41.7mm
Power Reserve
Marinemaster M-4038h
Prospex Sea41h
Water Resistance
Marinemaster M-40300m
Prospex Sea200m
MSRP
Marinemaster M-40$3,520
Prospex Sea$595

Full specifications

Case

5 specs
Diameter
40mm
41.7mm
Thickness
13mm
12.3mm
Lug-to-Lug
49.5mm
Lug Width
21mm
20mm
Water Resistance
300m
200m

Crystal & Dial

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

Movement

3 specs
Caliber
Sellita SW220-1
4R35
Power Reserve
38h
41h
Jewels
26
23

Pricing

1 specs
MSRP
$3,520
$595

Follow this matchup

Get a note when Fortis Marinemaster M-40 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.

Fortis Marinemaster M-40

Owners praise the Fortis Amber Orange for its gorgeous appearance and strong wrist presence, noting its crazy lume and 70-hour power reserve. The Doxa SUB 300T, described as having a superb, eccentric design with a highly legible dial and functional no-decompression bezel, uses an ETA 2824-2 movement. However, the SUB 300T's 42.5mm case wears large and its 14mm thickness is not ideal for dress shirts, though it boasts 1,200m water resistance. On balance, owners appreciate the Fortis Amber Orange for its striking aesthetics and impressive lume.

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.

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.