Police are at the scene where a number of services are suspended.
Unconfirmed reports suggest a shooting has taken place.
The airport wrote on Twitter: “We are working with the RCMP and responding to reports of a police incident outside YVR main terminal.
“Please follow here for the latest info — airport is currently open and safe with restricted access, please check with airline for flight information.”
They added: “UPDATE ON EVOLVING POLICE INCIDENT: We can confirm the situation has been contained at YVR. The airport is open and safe.
“Flights are operating. We will release more info as it becomes available. Check with your airline on the status of your flight before leaving for YVR.”