Casio PRO TREK PRG-340 Review: A Rugged, Eco-Friendly Watch Built For The Outdoor

Whether you are planning a weekend in the woods or a weeklong trek off the grid, having the right gear can make all the difference. Casio’s PRO TREK line has always been about rugged reliability and practical features for outdoor explorers, and now they’ve gone a step further by making sustainability part of the equation.

Meet the Casio PRO TREK PRG-340, a solar-powered, adventure-ready watch that’s tough, functional, and eco-conscious.

Eco-Friendly Build with Outdoor-Ready Materials

Casio has put serious thought into the PRG-340’s construction. The case, bezel, and case back are made from bio-based resin, which comes from renewable organic resources. The band options are just as outdoorsy and practical:

• PRG-340B-3 – This olive green cloth band made from CASTLON®, a 100% plant-derived nylon created from castor oil plants. It’s lightweight, durable, flexible at low temps, and even flame-retardant – perfect when you’re cooking over a campfire.
• PRG-340L-5 – This rugged coyote brown faux leather band, also flame-retardant, features a more classic look that transitions easily between outdoor gear and everyday wear alike, offering both practicality and aesthetic appeal.

We love the fact that not only do these materials hold up under harsh environments, but they also reduce environmental impact. It’s a win-win for eco-conscious adventurers.

Triple Sensor + Upgraded Display

Like its PRO TREK predecessors, the new PRG-340 comes equipped with Casio’s Triple Sensor technology, giving you three essential tools right on your wrist:

• Digital Compass – For navigation when GPS fails.
• Barometer/Altimeter – To track elevation changes and keep an eye on weather patterns.
• Thermometer – Essential for monitoring temps in the backcountry.

The watch also debuts a dual-layer LCD (duplex display), making the compass easier to read. The top layer shows compass graphics, while the bottom layer displays time and sensor readings. Casio slimmed down the LCD to reduce bulk, which means you get sharper visuals in a more streamlined package.

Powered by the Sun

Worrying about batteries on a long trip? Not here. The PRG-340 is equipped with Tough Solar technology, which converts light (sunlight or even fluorescent lamps) into energy. This keeps the watch running smoothly without needing frequent recharges or battery swaps, which is huge for long multi-day trips.

Outdoor-Ready Features

Beyond its eco-conscious build and Triple Sensor, the PRG-340 is loaded with features that make it a true adventure tool:

• 100m water resistance – Great for kayaking, fishing, or sudden downpours.
• Low-temp resistance (-10°C / 14°F) – Built to handle alpine or winter conditions.
• World time (48 cities) – Perfect for international travel.
• Sunrise/sunset data – Helps you plan treks around daylight hours.
• Super Illuminator LED backlight – Auto-activating, bright, and easy to read in total darkness.
• Stopwatch, countdown timer, 5 daily alarms – Essential for pacing hikes, workouts, or time-sensitive activities.

Specs at a Glance:

• Bio-based resin case & bezel
• CASTLON® cloth or faux leather flame-retardant band
• Triple Sensor (compass, barometer/altimeter, thermometer)
• Dual-layer LCD display
• Tough Solar charging system
• 100m water resistance
• -10°C/14°F low-temp resistance
• Sunrise/sunset data, world time, alarms, timers, stopwatch
• Weight: 52-55g
• Price: $280 (PRG-340L-5) / $290 (PRG-340B-3)

Why It’s a Must-Have

The Casio PRO TREK PRG-340 isn’t just a watch – it’s a field-tested survival tool that’s as practical in the wilderness as it is at a campsite or on a road trip.

• Backpackers & hikers will appreciate the altimeter and barometer for tracking progress and weather shifts.
• Climbers & mountaineers get peace of mind from the compass and durability in low temps.
• Campers benefit from the flame-retardant band that resists sparks from fires.
• Travelers will appreciate the world time and solar power for convenience anywhere in the world.

Final Verdict

Casio has managed to combine rugged performance with eco-conscious design in the PRO TREK PRG-340, making it one of the most versatile outdoor watches on the market. At under $300, it’s a killer value for anyone who loves exploring and wants a timepiece that won’t let them down—or the planet.

If your adventures take you off the beaten path, the Casio PRO TREK PRG-340 deserves a permanent spot on your wrist.