Claire Holt,She returns in series four and it is revealed that she is Will Benjamin's cousin.
Phoebe Tonkin,Tonkin appears in all series of the show.
Cariba Heine,Heine appears in all series of the show
i really like mackenziebuzan's idea because i think will and rikki should be together and i HATE bella...dont know hwy
though..really dont mean to be mean...
i heard and read that there will only be a season 4 in Autralia and in the UK instead of a season four there is going to be a whole new show called Mako:island of secrets