Hi Maria, The earphones have been designed to stay perfectly in place and not fall out, even during active movement or sport. The different tips supplied allow you to choose the ideal size for a secure fit and maximum comfort throughout the day.
For a detailed step-by-step guide on how to wear them correctly and ensure they stay securely in place, please see the 'Wearing your headphones' section of the online help guide available on our website. Sony Europe

Hi Maria, The earphones have been designed to stay perfectly in place and not fall out, even during active movement or sport. The different tips supplied allow you to choose the ideal size for a secure fit and maximum comfort throughout the day.
For a detailed step-by-step guide on how to wear them correctly and ensure they stay securely in place, please refer to the 'Wearing your headphones' section of the online help guide available on our website. Sony Europe

They also fit me well. You also get different sizes of the plastic parts, so you can customise the buds a little to your own ears.

This will vary from ear to ear. With my rather small ear canals, the buds fit well.

At least in my ears, the fit is very reliable.