Plans to transport the animals to a sanctuary in California by plane have stalled for months and now zoo officials are considering moving them by ground.
The new plan would see Toka, Thika and Iringa travel to the PAWS Wildlife Sanctuary near Sacramento, Calif., on trucks.
Julie Woodyer of Zoocheck Canada — a national zoo watchdog — says the trip would last about 50 hours, with several stops for refuelling and check-ups.
She says at least two veterinarians and six handlers would be accompanying the elephants on their journey.
The preliminary plan has been presented to the CEO of the Toronto Zoo for approval and will then be sent to city hall.
Toronto City Council voted in 2011 to send the three elephants to the U.S. facility after groups voiced concern about the animals' welfare.
Activists had previously said the zoo was in talks to borrow a Canadian Forces plane to transport the huge animals.
The Department of National Defence said in May that it was still considering helping with the move, but the animals would have to stay put until the fall.
U.S. officials had pegged the cost of transporting the animals by air at up to US$1 million.
Animal rights activist and former ''The Price is Right'' host Bob Barker has promised to pick up the tab.