Casio's new affordable F-B100W watches with step tracker sell out on launch, 3rd-party retailers list it for less

Casio's F-B100W went on general sale in Japan on August 7, and the company's own online store ran out of stock the same day. All three colorways — F-B100W-1AJF, -1BJF and -3AJF — moved from preorder to open purchase that morning and were gone within hours.

The speed of this happening isn't really hard to explain. At ¥8,800 (roughly $55) this is among the cheapest step-tracker and Bluetooth-equipped watches Casio has ever shipped, and it gets the icoic F-91W's (curr. $22 on Amazon) rectangular silhouette. That's a design people already own and are familiar with. Add more connectivity and a key daily-use feature, and it's unsurprising that this series drew a massive queue.

In case you missed our previous coverage (see here), here's what's inside the F-B100W. An accelerometer counts steps and shows the day's total on the LCD; Bluetooth handles automatic time correction and pushes step data into Casio's app for basic activity logging. There's no heart-rate sensor, no GPS, and no display aside from the standard segmented panel. The case measures 41.9 × 38.1 × 8.8 mm and weighs 26 grams, with a slitted biomass-plastic band. Casio quotes roughly two years from the battery.

The three finishes differ mainly in contrast. The -1AJF pairs a black case with a positive LCD and retro blue, red and yellow dial accents. The -1BJF is all black with a negative display and gray text. The -3AJF arrives in muted green with turquoise highlights.

Buyers who missed the window aren't entirely out of luck. Several Japanese third-party retailers still list stock across the range, though pricing is a whole different story — some of it is above Casio's own figure, while some listings are marked down. What Casio hasn't given is a restock date, or any commitment to selling the F-B100W outside Japan — and even if that happens, Japanese pricing rarely translates cleanly onto eventual US or European retail.

We will post an update if/when the F-B100W series is back in stock.