Hi rosmond,

welcome to Questions & answers..:smileyhappy:

hopefully the following information from the support pages tips & tricks may help..

Why does the volume become low during or after swimming?
The sound quality may deteriorate if water gets inside the headphone sections (A). When you use your Walkman in the pool, be sure to choose the size of earbud carefully so that it fits fully into your ear and then insert the headphone sections firmly into your ears, so that there is no gap to allow water to get in.

If water gets inside the headphone sections, hold your Walkman as illustrated and shake it about 5 times to remove the water. However, if there is still water is in the headphones, remove the earbud, put a dry cloth over the aperture of the headphone, and shake the headphones about 5 to 10 times.