Head-to-Head Comparison

Updated September 5, 2026

Casio MTP-S120L Solar Field vs Mido Ocean Star GMT

Casio's field watch meets Mido's diver

Quick Verdict

The Casio MTP-S120L Solar Field ($100–$150) offers Casio Tough Solar Quartz precision in the tier below the Mido Ocean Star GMT ($1,000–$1,500). The MTP-S120L Solar Field measures 42mm (49 x 42 x 10.9mm) and is rated 100m (10 ATM). The Ocean Star GMT counters with Swiss Made craftsmanship and 200m (20 ATM) water resistance. Both are exceptional watches for their respective tiers.

CasioMTP-S120L Solar Field$100–$150 Check price MidoOcean Star GMT$1,000–$1,500 Check price

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Casio

MTP-S120L Solar Field

$100–$150

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Mido

Ocean Star GMT

$1,000–$1,500

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Specifications Compared

Feature	Casio MTP-S120L Solar Field	Mido Ocean Star GMT
Price	$100–$150	$1,000–$1,500
Case Size	42mm (49 x 42 x 10.9mm)	44mm
Movement	Solar-Powered Quartz	Automatic Caliber 80 (Base ETA C07.661)
Caliber Type	Casio Tough Solar Quartz	Automatic (ETA C07.661 base)
Power Reserve	Months on a full solar charge; no battery replacement	80 Hours
Water Resistance	100m (10 ATM)	200m (20 ATM)
Crystal	Mineral Crystal	Sapphire with Double-sided AR
Case Material	Stainless Steel	Stainless Steel
Origin	Casio (Japan)	Swiss Made

Category-by-Category Analysis

🎨

Design & Aesthetics

Edge: Draw

Casio's design language vs Mido'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 Mido Ocean Star GMT offers Stainless Steel construction at 44mm with Sapphire with Double-sided AR. Both represent their brand's distinct design philosophy and heritage.

⚙️

Movement & Performance

Edge: Mido

Solar-Powered Quartz vs Automatic Caliber 80 (Base ETA C07.661)

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 Ocean Star GMT uses the Automatic Caliber 80 (Base ETA C07.661) (Automatic (ETA C07.661 base), 80 Hours reserve) at 21,600 vph (3 Hz). The Ocean Star GMT offers a longer power reserve.

📏

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 Ocean Star GMT at 44mm. Water resistance differs: 100m (10 ATM) vs 200m (20 ATM).

💰

Value & Cost of Ownership

Edge: Casio

Casio sits in the lower tier

The Casio MTP-S120L Solar Field sits at $100–$150 and the Mido Ocean Star GMT at $1,000–$1,500. 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 Sapphire with Double-sided AR and 80 Hours on the Ocean Star GMT. Service intervals are typically 5-7 years for both.

💧

Water Resistance

Edge: Mido

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

The MTP-S120L Solar Field is rated to 100m (10 ATM) while the Ocean Star GMT handles 200m (20 ATM). The Ocean Star GMT 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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Mido

Ocean Star GMT

Choose the Mido Ocean Star GMT if you value Automatic (ETA C07.661 base) technology, Swiss Made heritage, and 44mm proportions. At $1,000–$1,500, the Automatic Caliber 80 (Base ETA C07.661) with 80 Hours power reserve makes it a compelling choice.

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The Bottom Line

The Casio MTP-S120L Solar Field and Mido Ocean Star GMT represent two distinct approaches to fine watchmaking — the Casio bringing Casio (Japan) tradition while Mido delivers Swiss Made engineering.

Frequently Asked Questions

The Mido Ocean Star GMT is the better buy if you want a mechanical movement; the Casio MTP-S120L Solar Field is the better buy if you want solar power and quartz accuracy with no servicing. For water, the Mido Ocean Star GMT 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 $1,000–$1,500), 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 Mido Ocean Star GMT 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 Ocean Star GMT at 44mm with 200m (20 ATM) is similarly capable. The MTP-S120L Solar Field uses Mineral Crystal while the Ocean Star GMT uses Sapphire with Double-sided AR. Sapphire resists scratches noticeably better than mineral glass.

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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.