Many reasons have been suggested for breaching humpback whales.
They often breach when they are in groups, suggesting social reasons, such as an assertion of dominance, courting or warning of danger Other widely accepted reasons is to dislodge parasites from the skin or that the behaviour may simply be a form of play. Some believe that a breach allows the whale to breathe in air that is not close to the surface, which may aid breathing in rough seas. From my experience it is often the young whales that do repeated breaches which agree with the play theory and when we have rough water on a whale watching day we also seem to have more breaches. To be honest the reason is not that important the action is just spectacular.