A new mermaid named Ondina arrives and is afraid that Zac Blakely is a threat to mermaid pods everywhere, but what she doesn't realize is that there is another merman in addition to Zac in town called Erik bent on seizing Mako Island for himself.
Brooke Nicole Lee, Gemma Forsyth, Dominic Deutscher, Amy Ruffle, Chai Romruen, Kerith Atkinson and Rowan Hills are confirmed to be returning for season 2.
Lucy Fry and Ivy Latimer will not be returning for season 2.
Isabel "Issi" Durant has been confirmed to be joining the cast for it's second season as Ondina.
Canadian Actress, Allie Bertram has been confirmed to be joining the cast for it's second season as Mimmi.
Actor/Model Alex Cubis has been confirmed to be joining the cast as Erik.
Later on one Twitter user tweeted that there will be a conection between past mermaids of H2O and now Mako Mermaids, so please bring back H2O mermaids and Jonathan retweeted "Yes. Good guess! :)"
Jonathan tweeted that they met on Monday on 6th January with the main cast.
Filming for Season 2 is planned to wrap up in July 2014, according to the article on Gold Coast Bulletin.com
Evie will become a mermaid this season according to Jonathan M. Shiff twitter photo where there are Sirena, Mimmi, Ondina and Evie in Moon Pool.
It has been confirmed that Ondina and Erik will be a couple. Both Alex Cubis and Isabel Durant tweeted that it is their last day of filming with their "onscreen lover" and "mermate".
It is not known if Evie will get a moon ring, due to all the mermaids have a moon ring.
It has been said by Jonathan M. Shiff that the release date for the first half of Season 2 will be in January 2015.