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Seiko 5 SNK809 vs Citizen Eco-Drive BM8180

Both are field / explorer watches in the entry tier — here's how the specs differ and which to pick.

Last verified 2026-06-11 · specs from manufacturer data · tier = price band, confirm the live price at the retailer

SpecSeiko 5 SNK809Citizen Eco-Drive BM8180
MovementAutomaticSolar / light-powered
Water resistance30m100m
Case size37mm37mm
Crystalhardlexmineral
StyleField / explorerField / explorer
Price tierEntryEntry

Which should you buy?

Where to buy

Check the Seiko 5 SNK809 price on Amazon →

Check the Citizen Eco-Drive BM8180 price on Amazon →

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FAQ

What's the difference between the Seiko 5 SNK809 and the Citizen Eco-Drive BM8180?
Both are field / explorer watches in the entry tier. The Seiko 5 SNK809 is automatic, 30m water resistance, 37mm, hardlex crystal; the Citizen Eco-Drive BM8180 is solar / light-powered, 100m water resistance, 37mm, mineral crystal.

Which has better water resistance, the Seiko 5 SNK809 or the Citizen Eco-Drive BM8180?
The Citizen Eco-Drive BM8180, rated 100m, versus 30m on the other. Pick 100m or higher for swimming and 200m+ for diving.

Which is better value, the Seiko 5 SNK809 or the Citizen Eco-Drive BM8180?
Both sit in the entry tier, so it comes down to movement, water resistance and case size — see the spec table above.

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