This morning the Russo Bros. Tweeted an image of a note asking people to not spoil Avengers: Infinity War after they see it, and the note also had something interesting on it (more on that after the Tweet):
— Russo Brothers (@Russo_Brothers) April 3, 2018
They will not be showing Infinity War to anyone prior to the world premiere in Los Angeles. That’s on Monday the 23rd. Press screenings begin the day after on the 24th. Social media embargoes lift on the 23rd after the premiere, and then reviews are allowed the next day.
This is Star Wars level secrecy they’re doing with the movie. It means the earliest people will see it who are not press will be the evening of Tuesday night in the US with the first screenings taking place in Australia then.