Head-to-Head Comparison

Updated September 5, 2026

Casio Pro Trek PRG340-1 vs Citizen Promaster Sea Eco-Drive Diver

Casio's timepiece meets Citizen's diver

Quick Verdict

The Casio Pro Trek PRG340-1 ($150–$250) offers Tough Solar Quartz (No Battery Change) precision in the tier below the Citizen Promaster Sea Eco-Drive Diver ($250–$500). The Pro Trek PRG340-1 measures 54.7 × 51.7 × 15.1mm 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.

CasioPro Trek PRG340-1$150–$250 Check price CitizenPromaster Sea Eco-Drive Diver$250–$500 Check price

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Casio

Pro Trek PRG340-1

$150–$250

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Citizen

Promaster Sea Eco-Drive Diver

$250–$500

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Specifications Compared

Feature	Casio Pro Trek PRG340-1	Citizen Promaster Sea Eco-Drive Diver
Price	$150–$250	$250–$500
Case Size	54.7 × 51.7 × 15.1mm	44mm
Movement	Tough Solar (Solar Quartz)	Eco-Drive Caliber E168
Caliber Type	Tough Solar Quartz (No Battery Change)	Citizen Eco-Drive (Solar Quartz)
Power Reserve	Tough Solar (Rechargeable)	—
Water Resistance	100m (10 ATM)	200m (20 ATM) ISO 6425
Crystal	Mineral Glass	Mineral Crystal
Case Material	Bio-Based Resin	Stainless Steel
Origin	Casio (Japan)	Made in Japan

Category-by-Category Analysis

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Design & Aesthetics

Edge: Draw

Casio's design language vs Citizen's approach

The Casio Pro Trek PRG340-1 features a Bio-Based Resin case at 54.7 × 51.7 × 15.1mm with Mineral Glass 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

Tough Solar (Solar Quartz) vs Eco-Drive Caliber E168

The Pro Trek PRG340-1 runs the Tough Solar (Solar Quartz) (Tough Solar Quartz (No Battery Change), Tough Solar (Rechargeable) 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: Citizen

54.7 × 51.7 × 15.1mm vs 44mm — different wrist presence

At 54.7 × 51.7 × 15.1mm, the Pro Trek PRG340-1 has a bolder wrist presence compared to the Promaster Sea Eco-Drive Diver at 44mm. Water resistance differs: 100m (10 ATM) vs 200m (20 ATM) ISO 6425.

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Value & Cost of Ownership

Edge: Casio

Casio sits in the lower tier

The Casio Pro Trek PRG340-1 sits at $150–$250 and the Citizen Promaster Sea Eco-Drive Diver at $250–$500. On the specs that outlast any price: the Pro Trek PRG340-1 uses Mineral Glass with Tough Solar (Rechargeable), 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 Pro Trek PRG340-1 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

Pro Trek PRG340-1

Choose the Casio Pro Trek PRG340-1 if you prioritize Tough Solar Quartz (No Battery Change) engineering, Casio (Japan) craftsmanship, and 100m (10 ATM) water resistance. At $150–$250, it delivers Tough Solar (Solar Quartz) with Tough Solar (Rechargeable) 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 Pro Trek PRG340-1 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 Pro Trek PRG340-1 sits a band lower ($150–$250 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 Pro Trek PRG340-1 offers better upfront value, sitting a tier lower at $150–$250. 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 Pro Trek PRG340-1 at 54.7 × 51.7 × 15.1mm 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. The Pro Trek PRG340-1 uses Mineral Glass while the Promaster Sea Eco-Drive Diver uses 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.