The search for William Pilkenton of Bellingham, Wash., was suspended when darkness fell, The Bellingham Herald reported. Teams of volunteers, police and other agencies planned to continue Sunday.
Pilkenton vanished while beachcombing with his parents near the bed and breakfast where they were staying.
Susan Boyes of the Royal Canadian Mounted Police said volunteers had turned out in force, Canwest News Service reported. They included employees of Parks Canada and others with experience in the wilderness.
The search included the waters off Duffington Cove, the woods near the beach and the town of Tofino. Tofino Search and Rescue sent out an e-mail describing the clothes the boy was wearing.
"He has ADD (Attention Deficit Disorder), and received his daily medications this morning. He is a friendly boy and loves water and animals, and should respond if he hears his name," the e-mail said.