Can you take your phone in a sauna?

The short answer is no, you should not take your phone into a sauna. Saunas run far hotter than the temperature range phones are built to handle, and a traditional sauna adds humidity and steam on top of that. One quick session might not visibly hurt anything, but you are gambling with battery health, the screen, and the internal electronics every time. It is much safer to leave the phone outside.

The short answer

Phones and saunas are a poor match for one simple reason: the heat is well outside what your phone is designed to tolerate. Most smartphones are built to operate comfortably up to roughly 95°F (35°C), and saunas run many tens of degrees hotter than that. A traditional sauna piles humidity and steam onto the problem.

You may get away with it once or twice. But the risk is real and it is cumulative, so the sensible habit is to leave your phone in a locker, a bag, or just outside the door. If you want music or a timer, there are easy ways to get both without putting your phone in harm’s way, which we cover below.

The temperature mismatch

The core issue is a gap between two numbers: how hot a sauna gets, and how much heat a phone can take. They do not overlap.

Manufacturers publish operating and storage ranges for their devices. As a general, widely-stated guide, most smartphones are rated to operate up to roughly 95°F (35°C) and to be stored (powered off) up to roughly 113°F (45°C). Exact figures vary by model, so check your own device’s specifications, but those numbers are typical. Now compare them to a sauna:

Even the gentlest sauna sits above a phone’s normal operating range, and a traditional sauna is far beyond it. For more on why these rooms run so hot, see our guide on how hot a sauna should be. The takeaway here is simple: there is no sauna setting that brings the air down into your phone’s comfort zone.

What heat actually does to a phone

It helps to know why the heat matters, rather than treating it as a vague warning. A few specific things happen as a phone gets too hot:

• Battery stress. Lithium-ion batteries dislike heat. High temperatures accelerate the chemical aging that permanently reduces capacity, so a phone repeatedly cooked in a sauna may hold less charge over time. In more extreme cases, heat raises the risk of swelling, which can push the screen or back panel out of place.
• Thermal shutdown. Phones have built-in protection that throttles performance or shuts the device down when it overheats. You may pull your phone out to find it dark and unresponsive until it cools, which is the device defending itself.
• Screen and adhesive. OLED screens and the adhesives that hold a phone together are sensitive to heat. Prolonged high temperatures can affect display behaviour and soften the glue and gaskets that keep the phone sealed and assembled.
• Long-term degradation. Much of the damage is not dramatic or immediate. It is the slow accumulation of stress on the battery and seals that shortens the phone’s useful life. The absence of a cracked screen after one session does not mean nothing happened.

Humidity makes a traditional sauna worse

Heat is only half the problem in a traditional sauna. The other half is moisture. Ladling water onto the hot rocks produces bursts of steam, and that humid air is exactly what electronics are built to avoid.

A common assumption is that a water-resistant phone is safe here. It is not, and the reason is worth being clear about: water resistance is not heat resistance. Those ratings are tested at normal temperatures, typically against brief immersion in still water, and say nothing about tolerance for hot, humid air. Worse, the seals and adhesives that create water resistance can soften or degrade with repeated heat exposure, so a sauna can quietly undermine the very protection you are counting on. Steam can also creep into ports and around the screen edges in ways a quick dunk test never simulates.

If you want to understand the difference in conditions between the two main sauna styles, our infrared vs traditional sauna comparison lays out how each one heats the room. For phones, the short version is that traditional saunas are the riskier of the two because they add moisture to the heat.

What about infrared saunas?

An infrared sauna is cooler and drier than a traditional one, which makes it the most tempting place to sneak a phone in. It still is not a good idea.

Infrared saunas run roughly 110-140°F (43-60°C) because they warm your body directly rather than heating the air. That is gentler on you, but it is still above your phone’s operating range and at or above its storage limit. The room is also full of infrared energy, which the panels emit to heat objects directly, and your phone is an object in that path. The lower humidity removes the steam risk, but the heat problem remains. So while infrared is the lesser of two evils, the answer is still to leave the phone outside.

Smartwatches and earbuds get the same caution

If phones are out, the rest of your gadgets should follow. Smartwatches like an Apple Watch, fitness trackers, and wireless earbuds all contain the same heat-sensitive batteries and electronics, and they face the same heat and humidity you do. Manufacturers generally advise against using them in saunas and steam rooms for exactly these reasons.

The water-resistance point applies here too. A watch rated for swimming is not rated for sauna heat, and the gap between those two things is precisely where damage happens. The simple rule covers everything: if it has a battery, it stays outside. This sits alongside the broader advice on what to leave behind in our guide to what to wear in a sauna, which also covers why metal jewellery is best removed.

If you want music, audio, or a timer

The good news is that almost everything people want their phone for in a sauna can be handled without bringing the phone in. A few practical alternatives:

• Bluetooth speaker, phone outside. Keep your phone in a cooler spot just outside the room and stream to a Bluetooth speaker. Bluetooth easily reaches through a sauna wall or open door, so your music plays inside while the heat-sensitive device stays safe. Place the speaker itself somewhere cooler too if you can.
• Sauna-rated audio. Some saunas come with built-in, heat-rated speakers, and a small number of standalone speakers are specifically designed to tolerate high heat and humidity. These are the only audio devices that genuinely belong in the hot room.
• A simple timer. A sand timer or a basic wall-mounted thermometer-and-timer tracks your session with nothing to damage. Many people simply check a clock before going in.

There is also a case for leaving the phone behind entirely. For a lot of regular sauna users, the screen-free break is part of the point, and a session is a rare stretch of time with no notifications. If you are still building your routine, our guide on how to use a sauna covers session length, cooldowns, and getting the most from the time.

A note on public saunas and etiquette

Two more reasons to leave the phone outside come up specifically in public saunas, gyms, and spas. The first is theft and security — a phone left on a bench in a shared space is an easy target, and you cannot keep a close eye on it while you relax. A locker is far safer.

The second is etiquette and privacy. Saunas are quiet, communal, often low-clothing spaces, and a phone, especially a camera, makes other people understandably uncomfortable. Many venues ban phones outright for this reason. Even where they are tolerated, scrolling and taking calls cuts against the calm that everyone else came for. Leaving it in your locker is both the polite move and the safe one.

The bottom line

Can you take your phone in a sauna? You can, but you shouldn’t. Saunas run well above the temperature range phones are built for, traditional saunas add steam and humidity on top of that, and even cooler infrared saunas sit above your device’s operating limit. The damage, when it comes, is often the slow kind: a weakening battery, stressed seals, a shorter lifespan. Water resistance will not save you, because water resistance is not heat resistance.

The fix is easy. Leave the phone, watch, and earbuds outside, use a Bluetooth speaker placed somewhere cooler or a simple sand timer, and treat the session as a screen-free break. If you are setting up a space of your own and want to plan around comfort rather than gadgets, start with the infrared saunas we recommend.