Back in March, we gave the Casio F-91W the full review treatment and walked away convinced it’s one of the best $20 purchases in all of watchmaking. A big part of that charm is that Casio has left the thing alone since 1989. There’s been no screens beyond the LCD, no apps, no charging cable – it’s just a no nonsense watch that we love.
So imagine our surprise when Casio decided to bring that entire formula into 2026 with the new F-B100W.
Same Wrist, Slightly More Watch
At a glance, this is the 1980s Casio digital blueprint we love to death. It sports the same angular resin case, four side pushers, integrated strap, and those signature blue, red, and gold faceplate accents on the black model.
But if you look just a bit closer, though, you’ll quickly realize that it’s not a carbon copy. The case measures 38.1mm across and 8.8mm thick at 26 grams, which means it wears a touch larger than the featherweight 35.2mm, 21-gram F-91W. The strap’s outer face is pulled straight from the F-91W, while the inner side get a some new ventilation slits. The whole thing is also now molded from bio-based resin.
Three versions exist so far including the classic black, a beautiful looking sage green with teal text, and a blacked-out reverse LCD that unfortunately hasn’t even made it out of Japan yet.
The 21st Century Stuff
An onboard accelerometer counts up to 999,999 steps, plots your last seven hours as a tiny bar graph on the dial, and lets you set daily goals between 1,000 and 50,000. It’ll even beep at you for sitting still too long, which admittedly, is one of our favorite features of the Apple Watch.
Pair it to the CASIO WATCHES app over Bluetooth and the watch sets its own time, logs your activity history, tracks roughly 300 world time cities, and can even ping your misplaced phone. Beyond that, you get five daily alarms, a countdown timer, and a 1/100-second stopwatch with 200-lap memory.
The Fine Print
Of course all of that technology is bound to create some trade-offs with the OG version. Battery life drops from the F-91W’s legendary seven years to roughly two. That is a major difference for sure, but it is still a CR2016 coin cell so you don’t have to worry about the nightly charging ritual.
It’s also worth noting that Casio rates it simply as “water resistant” with no depth figure, so we’d treat it as splash-proof and nothing more.
Spec Sheet
Model: Casio F-B100W
Case Size: 41.9 x 38.1 x 8.8mm
Case Material: Resin
Weight: 26g
Water Resistance: Water resistant (everyday use, no ATM rating)
Movement: Quartz, ±15 seconds/month (unsynced)
Battery Life: Approx. 2 years (CR2016)
Connectivity: Bluetooth via CASIO WATCHES app
Step Tracking: Up to 999,999 steps with hourly graph
Band: Bio-based resin, vented
Colorways: Black, Sage Green, Black Reverse LCD (Japan only)
Country of Origin: Thailand
Pricing & Availability
The F-B100W launched in Japan at ¥8,800 on August 7th and sold out through Casio’s official store that same day. It’s now listed on Casio UK at £55 (~$74) as “available soon” in black and sage green. Unfortunately for our stateside readers, Casio hasn’t confirmed a US release just yet.
Recap
Casio F-B100W
Casio grafts Bluetooth and a step tracker onto its most iconic digital watch design for £55 (~$74), and Japan’s entire launch allocation was gone within hours.
