The bubblehead charm works wonders, and his private swimming lessons with Barty mean he makes his way to the bottom in record time. Hermione and Ron are there, along with Cho Chang and a young blonde girl who he assumes is Fleur's Sister. It takes him only a moment to realise that he’s supposed to rescue Ron and then leave Hermione for Viktor. As much as he rolls his eyes, he releases Ron from the seaweed and makes his way back to the surface.