Rugby Southland confirmed the significant coup on Friday, the same day Alaimalo will make his debut for the Highlanders in the opening match of the 2021 Super Rugby Aotearoa season since moving south from the Chiefs.
By signing for Southland, the 25-year-old will also have a new side to play for in the NPC as he joins younger brother Charles, who has been at the Stags for the past two seasons, in Invercargill.
According to a report from Stuff, Alaimalo is believed to have turned down offers from bigger provincial unions to join Southland.