Using a mobile phone while driving is **dangerous** and **prohibited** in Spain, unless you use a **hands-free** device. This is because using a mobile increases the risk of accidents by distracting the driver. When you talk on the phone, your attention is diverted from the road, which can lead to errors such as misjudging distances or missing important signals.

Even with a hands-free device, the risk does not completely disappear, as part of your attention remains focused on the conversation. Therefore, it is recommended to stop the vehicle in a safe place if you need to make a call. Additionally, it is important that conversations are brief and that you inform the other person that you are driving.

In summary, to ensure safety, **you should not use a mobile phone while driving** unless you have a hands-free device, and even then, you must be aware of the risks involved.