Toronto's Newstalk 1010 radio station says a source at the zoo has confirmed that the plan is to begin the move this morning — providing the huge animals co-operate.
Toronto City Council voted in 2011 to send Toka, Thika and Iringa to the facility near Sacramento after animal rights activists voiced concern for the welfare of the three aging pachyderms.
The journey by truck is expected to take about 50 hours, and national zoo watchdog Zoocheck Canada has said at least two veterinarians and six handlers will accompany the elephants.
Two Toronto zoo keepers were also planning to go along to help with the elephant's transition to their new home.
But they've reportedly been told they can only go as far as the U.S. border unless they sign a non-disclosure agreement preventing them from revealing anything that might happen on the U.S. leg of the trip.