Side by side

Serica Ref. 5303 Diving ChronometervsGrand Seiko SBGR321

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
SBGR321
Grand SeikoSBGR321
MSRP $5,200

At a glance

11 of 29 specs differ
Diameter
Ref. 5303 Diving Chronometer39mm
SBGR32140mm
Power Reserve
Ref. 5303 Diving Chronometer42h
SBGR32172h
Water Resistance
Ref. 5303 Diving Chronometer300m
SBGR321100m
MSRP
Ref. 5303 Diving Chronometer$1,768
SBGR321$5,200

Full specifications

Case

5 specs
Category
Diver
Dress
Diameter
39mm
40mm
Thickness
12.2mm
13mm
Lug-to-Lug
46.5mm
46.6mm
Water Resistance
300m
100m

Crystal & Dial

2 specs
Dial Color
Enamel Black
Black
Lume
Super-LumiNova
None

Movement

3 specs
Caliber
M100 COSC
9S65
Power Reserve
42h
72h
Complications
COSC
None

Pricing

1 specs
MSRP
$1,768
$5,200

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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.

Grand Seiko SBGR321

Grand Seiko SBGR321 owners and reviewers widely praise its attractive design, compelling dimensions, and robust movement. The watch features sharp case lines with contrasting brushing and polishing, a 40mm steel case that provides presence without bulk, and 100m water resistance. Its sunburst blue dial, inspired by the dawn sky over Mount Iwate, showcases Grand Seiko's signature finishing on applied markers and hands, with a red-tipped seconds hand. The 9S65 automatic movement is noted for its precision, running within specifications, with one source reporting a +5 to -3 seconds a day rate and a 3-day power reserve. A blue rotor with a crimson rim, also inspired by Mount Iwate, is visible through the display caseback. On balance, owners and reviewers rate the Grand Seiko SBGR321 highly for its exceptional finishing and compelling blue dial design at its price point.

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