https://www.techradar.com/news/overwatch-is-free-on-the-pc-for-this-weekend-as-grand-finals-kick-off

To celebrate and coincide with the grand finals of the Overwatch League, Blizzard is making the game free to play for all-comers this weekend.

And when we say this weekend, we mean a long weekend, starting on Thursday, July 26 at 11am PDT in the US (7pm in the UK, 4am July 27 AEST in Australia), running through until Monday, July 30 up until the end of the day, in other words 11:59 PDT (6:59am on Tuesday, July 31 in the UK, 4:59PM AEST in Australia).