Head-to-Head Comparison

Updated September 5, 2026

Casio MTP-S120L Solar Field vs Citizen Promaster Sea Eco-Drive Diver

Casio's field watch meets Citizen's diver

Quick Verdict

The Casio MTP-S120L Solar Field ($100–$150) offers Casio Tough Solar Quartz precision in the tier below the Citizen Promaster Sea Eco-Drive Diver ($250–$500). The MTP-S120L Solar Field measures 42mm (49 x 42 x 10.9mm) and is rated 100m (10 ATM). The Promaster Sea Eco-Drive Diver counters with Made in Japan craftsmanship and 200m (20 ATM) ISO 6425 water resistance. Both are exceptional watches for their respective tiers.

CasioMTP-S120L Solar Field$100–$150 Check price CitizenPromaster Sea Eco-Drive Diver$250–$500 Check price

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Casio

MTP-S120L Solar Field

$100–$150

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Citizen

Promaster Sea Eco-Drive Diver

$250–$500

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Specifications Compared

Feature	Casio MTP-S120L Solar Field	Citizen Promaster Sea Eco-Drive Diver
Price	$100–$150	$250–$500
Case Size	42mm (49 x 42 x 10.9mm)	44mm
Movement	Solar-Powered Quartz	Eco-Drive Caliber E168
Caliber Type	Casio Tough Solar Quartz	Citizen Eco-Drive (Solar Quartz)
Power Reserve	Months on a full solar charge; no battery replacement	—
Water Resistance	100m (10 ATM)	200m (20 ATM) ISO 6425
Crystal	Mineral Crystal	Mineral Crystal
Case Material	Stainless Steel	Stainless Steel
Origin	Casio (Japan)	Made in Japan

Category-by-Category Analysis

🎨

Design & Aesthetics

Edge: Draw

Casio's design language vs Citizen's approach

The Casio MTP-S120L Solar Field features a Stainless Steel case at 42mm (49 x 42 x 10.9mm) with Mineral Crystal protection. The Citizen Promaster Sea Eco-Drive Diver offers Stainless Steel construction at 44mm with Mineral Crystal. Both represent their brand's distinct design philosophy and heritage.

⚙️

Movement & Performance

Edge: Draw

Solar-Powered Quartz vs Eco-Drive Caliber E168

The MTP-S120L Solar Field runs the Solar-Powered Quartz (Casio Tough Solar Quartz, Months on a full solar charge; no battery replacement power reserve) at standard frequency. The Promaster Sea Eco-Drive Diver uses the Eco-Drive Caliber E168 (Citizen Eco-Drive (Solar Quartz), standard reserve) at standard. Power reserves are closely matched.

📏

Wearability & Fit

Edge: Casio

42mm (49 x 42 x 10.9mm) vs 44mm — different wrist presence

At 42mm (49 x 42 x 10.9mm), the MTP-S120L Solar Field wears more compactly on smaller wrists compared to the Promaster Sea Eco-Drive Diver at 44mm. Water resistance differs: 100m (10 ATM) vs 200m (20 ATM) ISO 6425.

💰

Value & Cost of Ownership

Edge: Casio

Casio sits in the lower tier

The Casio MTP-S120L Solar Field sits at $100–$150 and the Citizen Promaster Sea Eco-Drive Diver at $250–$500. On the specs that outlast any price: the MTP-S120L Solar Field uses Mineral Crystal with Months on a full solar charge; no battery replacement, against Mineral Crystal and a standard reserve on the Promaster Sea Eco-Drive Diver. Service intervals are typically 5-7 years for both.

💧

Water Resistance

Edge: Citizen

100m (10 ATM) vs 200m (20 ATM) ISO 6425

The MTP-S120L Solar Field is rated to 100m (10 ATM) while the Promaster Sea Eco-Drive Diver handles 200m (20 ATM) ISO 6425. The Promaster Sea Eco-Drive Diver offers superior water resistance.

Our Verdict

Casio

MTP-S120L Solar Field

Choose the Casio MTP-S120L Solar Field if you prioritize Casio Tough Solar Quartz engineering, Casio (Japan) craftsmanship, and 100m (10 ATM) water resistance. At $100–$150, it delivers Solar-Powered Quartz with Months on a full solar charge; no battery replacement power reserve.

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Citizen

Promaster Sea Eco-Drive Diver

Choose the Citizen Promaster Sea Eco-Drive Diver if you value Citizen Eco-Drive (Solar Quartz) technology, Made in Japan heritage, and 44mm proportions. At $250–$500, the Eco-Drive Caliber E168 with ample power reserve makes it a compelling choice.

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The Bottom Line

The Casio MTP-S120L Solar Field and Citizen Promaster Sea Eco-Drive Diver represent two distinct approaches to fine watchmaking — the Casio bringing Casio (Japan) tradition while Citizen delivers Made in Japan engineering.

Frequently Asked Questions

For water, the Citizen Promaster Sea Eco-Drive Diver is rated 200 m against 100 m, which is the difference between swimming and diving on one side and splashes on the other. On price, the Casio MTP-S120L Solar Field sits a band lower ($100–$150 against $250–$500), so it is the cheaper way into the category. Neither is better at everything; the spec table above shows movement, case size, water resistance and crystal side by side so you can weigh what matters to you. We do not test units, so this is the makers' data, not a bench result.

The Casio MTP-S120L Solar Field offers better upfront value, sitting a tier lower at $100–$150. However, the Citizen Promaster Sea Eco-Drive Diver may justify its premium with superior finishing, heritage, or resale value.

Both are suitable for daily wear. The MTP-S120L Solar Field at 42mm (49 x 42 x 10.9mm) with 100m (10 ATM) water resistance handles everyday situations. The Promaster Sea Eco-Drive Diver at 44mm with 200m (20 ATM) ISO 6425 is similarly capable. Both use Mineral Crystal.

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How This Page Was Made

Our comparisons are generated from a hand-maintained specification database and reviewed under our editorial standards. We use AI tools to assemble pages from that data. We don’t invent specs: every number traces back to the database, and when we correct an entry, the fix is applied site-wide. As an Amazon Associate, The Horologist earns from qualifying purchases.