Fishing in Fukushima with the CASIO PRO TREK 3500 (FIELD TEST)

Fishing in Fukushima with the CASIO PRO TREK 3500 (FIELD TEST)

Editor’s Note:
Once again CASIO honored us with an invite to their yearly outdoor equipment testing media junket. We’re always thrilled to be part of these events, and as has been and continues the AkihabaraNews legacy, we were the only foreign press in attendance - because that's how we roll on-location here in the big, big city!

This year sees CASIO upping their game as they introduce the most advanced multi-functional timepiece in their PRO TREK series for outdoor adventurers – the PRO TREK PRW-3500.

Initially released in February this year, the Triple Sensor Version 3 delivers altitude, barometric pressure, and direction readings that are more accurate than the previous models, whilst boasting sensors that are 95% smaller.

Of course this and the detailed specs below sound impressive but we didn’t just to just take CASIO’s word that this watch delivers – and they didn’t want us to, either.

So we leapt at the opportunity when we were invited to to test the Pro-Trek PRW-3500 out for ourselves. And there really is only one way to find out how a watch fares in the great outdoors, so that’s where we went.

Swapping skyscrapers for trees, highways for rivers, we ventured north to Lake Hibara in Fukushima prefecture.

Voyaging forth from Tokyo Station, one shinkansen, local train, and a taxi ride later, we pulled up at our rustic accommodation, a wooden-furnished guesthouse. Wonderfully quaint, with floral patterns adorning the furniture, the setting was cosy and homey, and somewhat incongruous with the gadget presented before us.

With watches distributed before a rather delicious dinner made with local ingredients, we naturally had some time to play with our new toys. First, let’s have a look at the vitals:

Pro Trek PRW-3500 Key Features & Specs


  • Water resistant to 200m.
  • Multi-band atomic-clock-based timekeeping (US, UK, Germany, Japan, China); receives time calibration radio signals automatically (6 times per day/up to 5 times a day in China)
  • CASIO’s TOUGH SOLAR power; charges continuously, even in artificial light
  • World time
  • Sunrise / sunset data
  • Thermometer


  • Manual memory measurements (up to 30 records, each including altitude, date, time)
  • Auto log data (high low altitudes, auto cumulative ascent and descent)
  • Trek log data (up to 14 records of high low altitudes, auto cumulative ascent, and descent of particular trek)

Digital Compass

  • Bidirectional calibration and northerly calibration function.


  • Atmospheric pressure tendency graph
  • Alarm alerts to sudden pressure changes

Sounds awesome?

Well, yes. It’s a super-gadget watch that charges through solar power basically forever and can automatically inform the wearer of sudden barometric pressure changes plus all of the above! But what does all this gadgetry mean in practice?


The Pro Trek PRW-3500 is extremely easy to fasten and sits really comfortably against the wrist. Even though it fastens with a rubber strap, it’s slightly ridged in the middle, allowing some air to circulate and stopping things from becoming too sweaty.

At 90g, it’s not heavy, but it is a little bulky - it’s clearly designed with hardened (and most probably male) outdoor-adventurers in mind as the timepiece felt too large on my wrist. To counteract this, I wore it a bit further up my arm than I would usually do and I soon forgot it was there.


The watch, if taken off the wrist, acts as a thermometer that is able to measure temperatures from -10°C to 60°C, although we hope that you never find yourself in circumstances where it records those extremes. If worn on the wrist, it will pick up and approximate body temperature, but the primary, intended function is measuring ambient outdoor temperatures.

Alarm and Light

I set the alarm to wake me up at the highly sociable time of 5.15am for some fishing practice. However, it’s just as well that I used my smartphone as the alarm is very quiet and only lasts for a few beeps, meaning it’s only good for alerting you if you’re already conscious - something we’ve found previously with Casio’s PRO TREK watches: they aren’t meant to be alarm clocks.

CASIO Excursion Tests New EXILIM EX-FR10 Action Cam & PRO-TREK Watch (GALLERY)

The light function feels little too brief, particularly if you’re trying to read altitude or atmospheric log data. Yet given that the watch charges through solar energy, or even artificial light, using CASIO’s proprietary ‘TOUGH SOLAR’ technology, it would be somewhat counterintuitive if it lit up for a long time.

Let the adventures begin...

The PRO TREK series has understandably developed a dedicated customer base among outdoor enthusiasts. Not only is the compass self-evidently beneficial, but the ability to track high and low altitudes over a set period will appeal to anyone who likes record-keeping - and if you’re attempting a multi-day, strenuous hike, who wouldn’t want to get some stats for bragging rights? Particularly useful is the function that measures elevation change, allowing a hiker to know how far up (or down) he or she advanced on a particular hike.

However, having already secured hikers as PRO TREK users, CASIO is keen to promote the water resistance of the PRW-3500 to capture new markets. This explains why we found ourselves at the edge of Lake Hibara with canoeing and black bass fishing on the agenda, rather than trekking one of the many trails that the Urabandai area boasts.

Admittedly, water resistance to 200m is not exactly needed for these activities, unless we accidentally snared Ebirah - a formidable shrimp kaiju who takes on Godzilla - and were dragged down to the deepest, darkest depths of the ocean. In all honesty, this was one thing we were happy not to be testing out.

Editor Reno’s Note: I totally made Phoebe replace her Loch Ness Monster-based anecdote with Ebirah, and I stand firmly behind this decision.

Adventure 1: Canoeing/Kayaking

The day started with persistent - and fairly insistent - rain that cleared up just in time for our canoeing. Which makes it all the more ironic that I got myself so thoroughly drenched that I had to be escorted back to the guesthouse for a change of clothes. My technique involved lifting the oars a little too high, therefore scooping a good amount of lake water all over me and into the canoe.

Of course, I am going to pretend that I did this entirely on purpose because I can confirm, that yes, the Pro-Trek PRW-3500 is definitely waterproof.

Canoeing is a matter of teamwork and, therefore, a matter of communication, which is not so easy given you’re not facing each other. However, my canoeing partner and I soon fell into a rhythm and were gliding across the lake, and very thankful that there wasn’t a strong wind.

Even for us first-timers, we travelled what seems a remarkable distance in a fairly short amount of time, which was why after just 10 minutes or so we were prompted to check our watches. We had been travelling in a steadily northerly direction, which helped us keep track of our location in the lake relative to our starting point. This may sound simple but with almost no developments aligning the shore to act as landmarks, it’s surprisingly easy to get disoriented.

The other option, of course, is to get really familiar with the topography of the surrounding mountains, which made for a spectacular backdrop. If you’re looking for a break away from people, crowds and grey, urban landscapes, the peaceful Lake Hibara and the Urabandai area would make a rewarding trip. It certainly struck me that it had been a long time since I’d seen such a vast extent of uninterrupted trees.

Adventure 2: Black Bass Fishing

The next test for our multifunction PRO TREKs would be fishing. First up, we learned to cast the line and reel it in at an even pace, where I also perfected the art of catching weeds. The best technique for bass fishing is to keep the lure at around 10 cm below the surface of the water, which means holding the rod higher and a steeper angle initially, and lowering it as the lure approaches you.

After a fair amount of practice, it was time to put our skills to the test on a boat trip out onto the lake. To guide us, CASIO had enlisted the help of professional fisherman Shingo, a member of the Japan Bass Pro Association, in which he ranks in the top 50.

Having been fascinated by pond life from a tender age of six, Shingo began black bass fishing at 13 and slowly built up a collection of fishing equipment over his teenage years. Shifting from hobbyist to professional, he made his debut at the age of 23, but he says that that was still just the beginning. Now with 30 years of fishing experience to his name, he says it took an endless amount of trial and error, practice and determination before he felt he had acquired a decent level of skill.

For a professional like Shingo, the PRO TREK PRW 3500 is invaluable. First of all, and most simply, an accurate timepiece is absolutely essential for professional tournaments. “Even if I am just one second late, I will be disqualified,” he explains.

However, what makes this watch really useful to all fishermen - professionals and amateurs/hobbyists alike - is the barometer and associated functions.

There is a broad consensus among the fishing community that atmospheric pressure greatly affects the behaviour of fish, although there is currently no conclusive scientific evidence, partially due to the difficulty in isolating barometric pressure from other variables associated with weather change. As Shingo explained to me, “Before a typhoon, you are able to easily fish, but after a typhoon, it is very difficult. In stormy conditions that stir up the water, fish tend to take refuge and are reluctant to feed.

Best fishing conditions are believed to be after a sudden change in atmospheric pressure, in particular falling pressure. Fortunately, the Pro Trek PRW-3500 contains an alarm-setting function that will notify the wearer to exactly that. When enabled, the watch takes a barometric pressure reading every two minutes and beeps if there is:

(1) a sudden fall in pressure;
(2) a sudden rise in pressure;
(3) a sustained rise in pressure, changing to a fall; or
(4) a sustained fall in pressure, changing to a rise.

Shingo also takes into account the direction of the wind and the position of the sun in the sky, which means he regularly relies on the compass. “You have to understand the right fishing conditions and the right places to look for fish.

When we set out on boat fishing, the early morning rain had finally subsided and barometric pressure had maintained a consistent low from the night before, when we started monitoring it via our watches. Whilst not perfect conditions, the low pressure was apparently favourable for fishing.

After having a few line-casting slip-ups (releasing the catch before trying to cast is essential if you don’t want to look like you’re attempting to swat mosquitoes in the air), several fish did chase my lure. However, whether the conditions weren’t quite right, luck wasn’t on my side, or - most likely - I just don’t have the knack of casting and reeling in the lure at an appropriate pace and depth, the black bass eluded me.

They didn’t elude Shingo though, who returned from an outing with several bass stored in a tank to show us.

Overall Impressions

Would we take the CASIO PRO TREK PRW-3500 on an outdoor adventure? Undoubtedly, yes – its triple-sensor system, solar charging ability, and water resistance is a solid offering for outdoors enthusiasts. In particular, the barometric pressure change alert function is really valuable in forewarning of low pressure fronts that could be dangerous or disruptive. However, given the trend towards smart watches and data integration, it would be interesting to see one released with a GPS function, as Casio is currently rolling out in their G-SHOCK series. For us data geeks, there’s nothing like putting the stats on a map...

Current Retail Prices:

  • PRO TREK PRW-3500-1 (silver): ¥42,000 (~$350)
  • PRO TREK PRW-3500-Y1( blue): ¥44,000 (~$365)
  • PRO TREK PRW-3500-Y4 (orange): ¥44,000 (~$365)

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Contributor Phoebe Amoroso is a serial Japanophile, fascinated by the intersection between society and technology. A Brit with a quintessential academic background in geography, media and communications, she divides her time between Japanese studies, journalism, and eating. Her interests include the social psychology of the Internet, technology and everyday life, urban design and planning, sustainability, cities, the Internet of things, cross-cultural studies, and food – lots of glorious food. She likes karate but secretly dreams of being a ninja or a Pokémon master. Or even a ninja Pokémon master.