The World Federation One Stop Fiqh

Ruling 366

In instantaneous immersive ghusl, water must cover the entire body in one go. However, it is not necessary for the entire body to be out of the water before starting the ghusl; rather, it will suffice if part of the body is out of the water and the person goes under the water completely with the intention of performing ghusl.37

37 An example of instantaneous immersive ghusl is when a person, with the intention of performing ghusl, dives/jumps into a swimming pool and in doing so completely immerses himself in the water; or, when a person who is already partly immersed in the water completely immerses himself with the intention of ghusl.