Casio MTP-S120L Solar Field vs Seiko Prospex "Turtle"
Casio's field watch meets Seiko's diver
Quick Verdict
The Casio MTP-S120L Solar Field ($100–$150) offers Casio Tough Solar Quartz precision at $400 less than the Seiko Prospex "Turtle" ($500–$1,000). The Prospex "Turtle" counters with Made in Japan craftsmanship and 200m (20 ATM) Diver water resistance. Both are exceptional watches for their respective price points.
Transparency — We earn a small commission on purchases made through our Amazon links. This doesn't affect our editorial independence.
Specifications Compared
| Feature | Casio MTP-S120L Solar Field | Seiko Prospex "Turtle" |
|---|---|---|
| Price | $100–$150 | $500–$1,000 |
| Case Size | 44.5mm | 45mm |
| Movement | Solar-Powered Quartz | Automatic Caliber 4R36 |
| Caliber Type | Casio Tough Solar Quartz | In-House Automatic Manufacture |
| Power Reserve | Months on a full solar charge; no battery replacement | 41 Hours |
| Water Resistance | 100m (10 ATM) | 200m (20 ATM) Diver |
| Crystal | Mineral Crystal | Sapphire Crystal |
| Case Material | Stainless Steel | Stainless Steel |
| Origin | Casio (Japan) | Made in Japan |
Category-by-Category Analysis
Design & Aesthetics
Casio's design language vs Seiko's approach
Movement & Performance
Solar-Powered Quartz vs Automatic Caliber 4R36
Wearability & Fit
44.5mm vs 45mm — different wrist presence
Value & Cost of Ownership
Casio is $400 more affordable
Water Resistance
100m (10 ATM) vs 200m (20 ATM) Diver
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.
Check Price on AmazonSeiko
Prospex "Turtle"
Choose the Seiko Prospex "Turtle" if you value In-House Automatic Manufacture technology, Made in Japan heritage, and 45mm proportions. At $500–$1,000, the Automatic Caliber 4R36 with 41 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Casio MTP-S120L Solar Field and Seiko Prospex "Turtle" represent two distinct approaches to fine watchmaking — the Casio bringing Casio (Japan) tradition while Seiko delivers Made in Japan engineering.