Side by side

Serica Ref. 5303 Diving ChronometervsSeiko Prospex Sea

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
Prospex Sea
SeikoProspex Sea
MSRP $1,500

At a glance

14 of 29 specs differ
Diameter
Ref. 5303 Diving Chronometer39mm
Prospex Sea43.5mm
Power Reserve
Ref. 5303 Diving Chronometer42h
Prospex Sea70h
Water Resistance
Ref. 5303 Diving Chronometer300m
Prospex Sea200m
MSRP
Ref. 5303 Diving Chronometer$1,768
Prospex Sea$1,500

Full specifications

Case

6 specs
Diameter
39mm
43.5mm
Thickness
12.2mm
13.3mm
Lug-to-Lug
46.5mm
51mm
Lug Width
20mm
22mm
Material
Stainless Steel
Titanium
Water Resistance
300m
200m

Crystal & Dial

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

Movement

4 specs
Caliber
M100 COSC
6R35
Power Reserve
42h
70h
Jewels
25
24
Complications
COSC
None

Pricing

1 specs
MSRP
$1,768
$1,500

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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 Sea owners and reviewers praise its Marinemaster-style aesthetic, excellent case finishing, and impressive LumiBrite lume. The watch is powered by the 6R15 movement with a 50-hour power reserve and comes with both a steel bracelet and a silicone strap. Some owners find the Seiko Prospex Sea to be a great value and a suitable first "proper" watch, while others report it is uncomfortably big, thick, and heavy on smaller wrists. Reviewers note the GMT function is secondary with a less prominent scale, and the bezel's quieter clicks may not appeal to all. On balance, owners and reviewers rate the Seiko Prospex Sea highly for its classic design and finishing at its price point.

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