Faced the same problem tis summer...the ports were very well locked, but water went through anyway.
From where you may ask?
From a construction error, the back side cover comes up after severe usage at the top left corner, near the camera
Follow the link below, it's an italian link but the pics are very usefull to understand what's going on...
Don't know if due to a lack of glue or not, the problem is that the assistance says i didn't close the ports...not true, the phone had a manufactory's error which is a SHAME
I've always been a deep Sony's customer, tv, cameras, videocameras, HI-Fi, mobiles, even alarm clock, but this time i was very disappointed, the assistance is telling me i'm a liar (they say i didn't close the ports...)!!!! tell me another thing but not that i'm a liar!
i will never buy any other Sony product in my entire life, where is Sony's style i 've been talking for long time to my friends...
Guido, an italian sad customer