Apple Watch

Sauna and onsen tracker apps for Apple Watch, compared (2026)

Seven apps that log sauna, cold plunge, and bath sessions from an Apple Watch, side by side. What each records on the wrist, what it costs, and why Furolog, which is ours, is the one to pick if your visit includes water as well as heat.

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Ganbanyoku: lying on hot stone, how to do it, and whether the Apple Watch comes along

岩盤浴 is a Japanese heat format that is not a sauna and not a bath: you lie on heated stone slabs in a 40°C room, dressed, for a long time. What it is, how a session goes, what it does to heart rate compared with a sauna, and what the watch makes of it.

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Apple Watch in the bath or at a sento: water resistance, soap, and heat

Apple Watch is water resistant, but that does not make every bath or sento visit risk-free. Learn what Apple says about soap, hot water, Water Lock, and care.

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Can you wear an Apple Watch in a sauna? What Apple says, and what actually happens

Apple's sauna guidance is more specific than "don't". Here is the exact rule for each model, what heat really does to the watch, and how sauna regulars wear one anyway.

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Can you wear an Apple Watch in an onsen? Heat, minerals, and what Apple's guidance means for hot springs

Apple Watch is rated for swimming, but a 42°C sulfur spring is not a pool. What the water resistance rating covers, which spring types are hard on the watch, and how to bathe with one sensibly.

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Which Apple Watch models have a water temperature sensor?

Not every Apple Watch can measure the water it is in. Here is which models have the sensor, how it works, and why it matters for logging onsen and sauna sessions.

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