How did each of the competitors breathe underwater in Harry Potter and the Goblet of Fire?

Answer 1

Gillyweed. It's a plant which allows him to grow gills for an hour so he can breathe under the water the same way fish do. Dobby gave it to him, in the movie this was changed to Neville Longbottom.
In Harry Potter and the Goblet of Fire, Harry Potter eats a handful of Gillyweed to sprout gills so that he could be able to breathe and swim underwater without drowning, so as to complete the Second Task of the 1994-95 Triwizard Tournament.

In both the book and the film adaptation of Goblet of Fire, Harry eats Gillyweed. However, in the book, Dobby has the idea for the Gillyweed and steals some Gillyweed from Severus Snape's office and gives it to Harry. In the film, however, Neville Longbottom steals the Gillyweed for Harry, not Dobby.
Dobby in the book; Neville in the movie.

Answer 2

Fleur Delacour and Cedric Diggory used a bubble head charm, which supplied them with fresh air.

Viktor Krum attempted to tranfigure into a shark, but managed to transfigure his head, but that worked well enough.

Harry used Gillyweed, (in the book dobby steals it from Snape's cupboard) in the film Neville gives it to him.

Answer 3

Oh my gosh, firstly it was the FOURTH book (Goblet of Fire) and he used Gillyweed. In the book, it was obtained via Dobby stealing it from Snape's private stores, but in the film adaption of the book it was Neville who gave Harry the Gillyweed.

Answer 4

In the Goblet of Fire, Harry uses Gillyweed that Dobby provided for him to complete the first TriWizard Task

Answer 5

his dad is Poseidon, God of the Sea

and cause hes freaking amazing, hot and different

Answer 6

Gillyweed which is given to him by Dobby in the book and Neville in the film.

Answer 7

gillyweed

Answer 8

Gillyweed.