The sea lion was spotted around 5:45 a.m. as it walked south in the center divide of northbound I-880, just south of Park Street, the CHP reported.
CHP Officer Sam Morgan said Oakland police handled the incident.
"They initially called us because it was in close proximity to the freeway," he said.
The sea lion was held in an Oakland police vehicle until personnel from the Marine Mammal Center arrived to take the animal, CHP Officer Peter Van Eckhardt said.
A Marine Mammal Center spokesman was not immediately available to provide an update on the sea lion's condition.