Now live on PlayStation 4 and Xbox One, the Overwatch Free Weekend lets you try Blizzard’s shooter for free until Monday, September 12 at 4pm PT/7pm ET. As the download instructions explain, you can grab the approximately 9GB (PS4) and 15GB (XB1) client directly from the store on your console:

PlayStation 4 (PlayStation Plus Not Required)

Turn on your PlayStation 4 and log in to your preferred local user.
Go to PlayStation Store and select “Search” from the top menu.
In the search field, type in “Overwatch”
Select “Overwatch Free Weekend” from the search results and then click “Download.”
Once the download and installation process is complete, click “Start” to begin!

Xbox One (Xbox Live Gold Required)
Turn on your Xbox One and log in to your Xbox Live account.
Go to the Xbox One Store, select “Search.”
In the search field, type in “Overwatch.”
Select “Overwatch: Origins Edition” from the search results and then click “Free Trial.”
Once the download and installation process is complete, click “Launch” to begin!

The online European PlayStation Store has a listing for the free weekend (click ‘Try Free Demo’), and so does the online North American PlayStation Store.
If you plan on picking up Overwatch: Origins Edition, it’s on sale for $49.79 USD/£39.99 until September 16. Here’s what transfers from the free weekend to the...