Tonga said: “I was really impressed with the plan the Eels have moving forward and I feel I’ll be able to play my best footy there.
“I want to thank the Titans – I’ve been with them since I was a young bloke coming into first grade.
“I’m hoping to take my footy to the next level and I feel like I’ll have the best opportunity to do that at the Eels under Steve Kearney.”
Eels coach Steve Kearney said: “Esi is a dynamic outside back that can add a lot to our squad and we’re looking forward to having him with us next year.
“He’s only young and had a bit of trouble with injuries last year, but has already shown he is a real threat out wide.”