Side by side

Serica Ref. 5303 Diving ChronometervsSeiko Prospex Sea Save the Ocean Special Edition

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

13 of 29 specs differ
Diameter
Ref. 5303 Diving Chronometer39mm
Prospex Sea Save the Ocean Special Edition45mm
Power Reserve
Ref. 5303 Diving Chronometer42h
Prospex Sea Save the Ocean Special Edition41h
Water Resistance
Ref. 5303 Diving Chronometer300m
Prospex Sea Save the Ocean Special Edition200m
MSRP
Ref. 5303 Diving Chronometer$1,768
Prospex Sea Save the Ocean Special Edition$625

Full specifications

Case

5 specs
Diameter
39mm
45mm
Thickness
12.2mm
13.2mm
Lug-to-Lug
46.5mm
47.7mm
Lug Width
20mm
22mm
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, index(es) and bezel

Movement

4 specs
Caliber
M100 COSC
4R36
Power Reserve
42h
41h
Jewels
25
24
Complications
COSC
None

Pricing

1 specs
MSRP
$1,768
$625

Follow this matchup

Get a note when Serica Ref. 5303 Diving Chronometer vs Seiko Prospex Sea Save the Ocean Special Edition 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.

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 Save the Ocean Special Edition

The Seiko Prospex Sea Save the Ocean Special Edition is widely praised for its attractive, unique, and textured dials, often described as having a "Grand Seiko feel" at a more accessible price point, with specific mentions of wave patterns, lagoon hues, and manta ray motifs. Owners appreciate the smooth bezel operation and satisfactory lume. Accuracy figures vary, with one owner reporting +5 seconds per day, while another notes a range from +1/+2 to about -6 seconds per day. The 6R35 movement offers a 70-hour power reserve, and some models feature sapphire crystals. Criticisms include a desire for exhibition casebacks and concerns about the quality and security of the stamped metal clasps and bracelets, which are frequently described as rattly or underwhelming, though this is noted as a common Seiko trait. Some owners are split on the number of Save the Ocean variations and dislike the cyclops magnifier.

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.