Kain Anderson made his NRL debut against the Dolphins at Kayo Stadium in Round 27 of the 2025 season. The venue will become his full-time training base.
The 24-year-old outside back has signed with the Dolphins through the end of 2028.
He will join the club's Top 30 squad for pre-season training next month, after developing through Canberra's State Cup system and NSW Cup competition.
Anderson is the brother of Grant Anderson, who has played for the Storm and Broncos and now represents the Warriors.
Dolphins CEO Terry Reader said the signing would strengthen the club's outside-back depth.
"Kain has worked hard for this opportunity at NRL level and has shown through his performances in NSW Cup that he has plenty to offer," Reader said.
Reader said: "He is a strong outside back who we believe can continue to develop in the system so we are excited to have him joining out Top 30 squad from 2027.
"Kain has already had a taste of NRL football and we're looking forward to seeing him take the next step in his career here with the Dolphins."