Side by side

Serica Ref. 5303 Diving ChronometervsSeiko Prospex Sea 1968 Heritage Diver's GMT Watch

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

Ref. 5303 Diving Chronometer
SericaRef. 5303 Diving Chronometer
MSRP $1,768

At a glance

11 of 29 specs differ
Diameter
Ref. 5303 Diving Chronometer39mm
Prospex Sea 1968 Heritage Diver's GMT Watch42mm
Power Reserve
Ref. 5303 Diving Chronometer42h
Prospex Sea 1968 Heritage Diver's GMT Watch72h
Water Resistance
Ref. 5303 Diving Chronometer300m
Prospex Sea 1968 Heritage Diver's GMT Watch300m
MSRP
Ref. 5303 Diving Chronometer$1,768
Prospex Sea 1968 Heritage Diver's GMT Watch$1,700

Full specifications

Case

3 specs
Diameter
39mm
42mm
Thickness
12.2mm
13.3mm
Lug-to-Lug
46.5mm
48.6mm

Crystal & Dial

3 specs
AR Coating
Yes
Anti-reflective coating on inner surface
Dial Color
Enamel Black
Black
Lume
Super-LumiNova
LumiBrite on hands, index(es) and bezel

Movement

4 specs
Caliber
M100 COSC
6R54
Power Reserve
42h
72h
Jewels
25
24
Complications
COSC
None

Pricing

1 specs
MSRP
$1,768
$1,700

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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.

Serica Ref. 5303 Diving Chronometer

Owners widely praise the Serica Ref. 5303 Diving Chronometer for its excellent wearability, definitive style, and smooth, confident bezel action. The dual scale on the bezel is noted as surprisingly useful, and the crown action, winding, and hacking are reported to work perfectly. One owner describes the Serica 5303-3 as gorgeous and unique, though another notes the crown can appear comically large. On balance, owners rate the Serica Ref. 5303 Diving Chronometer highly for its blend of unique design and robust functionality.

Seiko Prospex Sea 1968 Heritage Diver's GMT Watch

The Seiko Prospex Sea 1968 Heritage Diver's GMT Watch offers a 300-meter depth rating and a caller-style GMT complication powered by the Caliber 6R54 movement, which provides a 72-hour power reserve. Reviewers note its refined clasp with extensive micro-adjustment. However, the movement's accuracy, ranging from +25 to -15 seconds per day, is considered a drawback by some. Overall, reviewers highlight the Seiko Prospex Sea 1968 Heritage Diver's GMT Watch as a good reminder of Seiko's value, despite the wide accuracy range of its movement.

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