The switch will be thrown on the 34th annual Celebration of Lights Saturday.
Santa Claus will do the honours at 6:15 p.m., illuminating the waterfront park with an estimated 500,000 lights and 41 displays.
The familiar Celebration of Lights Arch across Front Street has also been reinstalled.
Spokesman Dean Holtz said activities kick off at 4 p.m.
'We have plenty of activities for the family," said Holtz. "There are two different horse-drawn wagon rides, face painting, food trucks, and a live band leading Christmas carolling starting at 5 p.m. Then, starting at 6:45 p.m. we'll have a 15-minute fireworks display."
Holtz said they've tweaked the Children's Village this year.
"What we've done, we've set up lighting and there will be music as well, kind of like a DJ dance floor in the middle of the houses to make it more fun for the kids," he said.
Sarnia's Celebration of Lights began in 1984 with 650 lights and nine displays.