Side by side

Serica Ref. 5303 Diving ChronometervsSeiko Prospex Sea Seiko Prospex 1965 Heritage Diver’s Watch Save the Ocean Limited Edition

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

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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 Seiko Prospex 1965 Heritage Diver’s Watch Save the Ocean Limited Edition

The Prospex Sea Seiko Prospex 1965 Heritage Diver’s Watch Save the Ocean Limited Edition is praised for its compact 40mm case and the new Caliber 6R55 movement offering a 72-hour power reserve. Owners and reviewers highlight the stunning dials as a strong suit for Seiko. However, the 6R movement's accuracy is a point of disappointment for some, who wish for improvements closer to other movements, though others accept it given the excellent overall package. Press images suggest the bracelet end links may appear disjointed. Overall, owners and reviewers rate the Prospex Sea Seiko Prospex 1965 Heritage Diver’s Watch Save the Ocean Limited Edition well, with the stunning dials and improved power reserve being the biggest reasons.

At a glance

13 of 29 specs differ
Diameter
Ref. 5303 Diving Chronometer39mm
Prospex Sea Seiko Prospex 1965 Heritage Diver’s Watch Save the Ocean Limited Edition40mm
Power Reserve
Ref. 5303 Diving Chronometer42h
Prospex Sea Seiko Prospex 1965 Heritage Diver’s Watch Save the Ocean Limited Edition72h
Water Resistance
Ref. 5303 Diving Chronometer300m
Prospex Sea Seiko Prospex 1965 Heritage Diver’s Watch Save the Ocean Limited Edition300m
MSRP
Ref. 5303 Diving Chronometer$1,768
Prospex Sea Seiko Prospex 1965 Heritage Diver’s Watch Save the Ocean Limited Edition$1,400

Full specifications

Case

4 specs
Diameter
39mm
40mm
Thickness
12.2mm
13mm
Lug-to-Lug
46.5mm
46.4mm
Lug Width
0mm
20mm

Crystal & Dial

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

Movement

4 specs
Caliber
Soprod M100
Seiko 6R55
Power Reserve
42h
72h
Jewels
0
24
Complications
COSC
None

Pricing

1 specs
MSRP
$1,768
$1,400
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