Casio Launches ‘Sauna Watch’ That Can Withstand Temperatures of up to 100 C

The Yomiuri Shimbun

20:00 JST, October 19, 2025

Casio Computer Co. on Friday launched a watch that can withstand temperatures of up to 100 C for use in a sauna.

Called “Sadokei,” the watch has a heat-resistant battery and is made with a moisture-resistant resin.

Casio’s first stretchable watchband makes the device easy to put on and take off. The watch also features a “sauna mode,” which can be activated at the press of a button. When the mode is activated, the big hand makes one full revolution in 12 minutes instead of 60.

Available in two versions — a white face with an orange band and a black face with a black band — the watch is being sold at online stores and electric appliance retailers with a price tag of ¥16,500, including tax.

Inspired by young Casio employees who were frustrated by not being able to check the time while in the sauna, the watch was developed over about three and a half years by a team of four. About 2,200 available units were sold out in nine minutes when the watch was launched on presale on a crowdfunding site in December last year.