You’re supposed to turn Bluetooth off when you don’t need it – how risky is it really?

You wake up and your smartwatch has already synced with your phone. On the way to work, your phone connects to your car. Later, you put in wireless earbuds. On

a crowded bus, dozens of other Bluetooth-enabled devices may be just metres away from yours.

You may not think about Bluetooth at all – it has become an almost invisible part of everyday life.

So what is actually happening when we leave Bluetooth switched on all day? And should we follow official advice that it’s best to turn it off when you’re not using it?

How does Bluetooth work?

Bluetooth is a short-range wireless technology that allows nearby devices to communicate without cables. Your phone might use it to send audio to earbuds, exchange information with a smartwatch or connect to your car.

Before many devices communicate, they go through “pairing”. This means when Bluetooth is on, your phone constantly sends out tiny digital handshakes, basically asking “is there anything I know nearby?”

This establishes a relationship between devices.

Sometimes these relationships can be compromised, although modern Bluetooth security can include authentication, encryption and protection against unauthorised access to information shared between devices. This means having Bluetooth switched on does not normally mean a stranger nearby can simply connect to your phone.

Modern operating systems add further controls. Android, for example, requires apps targeting Android 12 or later to request permission to connect with nearby Bluetooth devices.

What’s the official advice?

The Australian Cyber Security Centre recommends switching Bluetooth off when it is not being used because this removes a potential avenue for attack.

The reasoning is straightforward: if you do not need a wireless connection, disabling it removes a potential threat.

That does not mean leaving Bluetooth enabled will result in your phone being hacked. Cybersecurity advice often aims to reduce unnecessary risk rather than suggest an attack is likely.

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Read more: Police equipment can be tracked via Bluetooth. What about your phone, watch and headphones?

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For many people, however, switching Bluetooth off throughout the day is becoming less practical. Watches, hearing devices, wireless headphones, cars and other accessories increasingly rely on persistent connections.

The Bluetooth Special Interest Group – an international not-for-profit that oversees the development of Bluetooth technology – continues to publish security notices and recommends users install manufacturers’ latest software updates.

What happens if you leave it on all day?

Leaving Bluetooth on means your phone remains capable of using Bluetooth services, including communicating with devices you have already paired. This means scanning happens in the background. So when you walk through an airport or a crowded street, your phone is quietly announcing its presence to the environment.

This creates another possible security risk, because attackers could potentially exploit weaknesses in Bluetooth technology to access your device.

A useful comparison is your front door. Having Bluetooth enabled is not like leaving the door wide open. It is more like having another door to your house – modern security can make that door difficult to get through but removing the door altogether removes one possible way in.

The technology is getting better – but also more complicated

Modern Bluetooth incorporates security features many older versions lacked. Our Bluetooth ecosystem is also expanding – and the phone may not always be the weakest link.

A recent Australian example demonstrates this.

In September, independent cybersecurity testing examined inexpensive smart glasses being sold in Australia.

Researchers found some could be accessed by a nearby attacker through Bluetooth without a password. The attacker could potentially control the glasses and access stored photos and videos.

The problem was not Bluetooth suddenly becoming insecure – it was the devices that had been poorly secured.

The case has since attracted regulatory attention. Australia’s Privacy Commissioner has launched an investigation into the Chinese company behind the app used by some of the glasses following concerns about its handling and security of personal information.

As more everyday objects acquire Bluetooth connections, security increasingly depends not just on your phone but on the quality of everything you connect to it.

So should you turn Bluetooth off?

You don’t need to stop using Bluetooth completely but a few simple habits can reduce unnecessary exposure:

1. Turn Bluetooth off when you don’t need it, particularly for extended periods
2. Keep your phone and Bluetooth accessories updated so known security vulnerabilities are patched
3. Reject unexpected pairing requests from devices you don’t recognise
4. Remove old or unused Bluetooth connections, including rental cars or shared devices
5. Check which apps have Bluetooth permission and disable access for apps that don’t need it.

For everyday users, leaving Bluetooth on does not mean strangers will access your phone.

But keep your phone and connected devices updated, reject unexpected pairing requests, remove devices you no longer use and switch Bluetooth off when you do not need it.

Meena Jha does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.