The feature is regularly a $2,500 option.
The free trial is available on vehicles built since September 2014 and enables automatic steering, speed, lane changing and parking with Summon.
"Once your trial begins, you'll receive an e-mail with instructions for permanently upgrading your Tesla," the automaker said in a message to owners.
Autopilot is at the vanguard of the movement toward self-driving cars.
Tesla touts the feature as helping to avoid crashes from the front and sides, along with preventing the car from wandering off the road. It can also help the driver find a parking space.
The Autopilot features are progressively enabled over time with software updates.
Edmunds says: This is a great way for Tesla owners to get a preview of the self-driving future.