The defender has been their top transfer target since the window reopened, and they reached an agreement on personal terms with him weeks ago.
However, the clubs initially could not agree on the fee, partly because Bologna owed Basel 50% of whatever they made from his departure.
After a week-long stall in negotiations, both clubs have finally reached an agreement. According to Fabrizio Romano, the Italian club has agreed to sell Calafiori to Arsenal for €40 million plus €5 million in add-ons and a sell-on clause.
This resolution ends a long-running saga, with some reports suggesting the transfer could have been hijacked by other clubs.
The defender will be delighted, as he has been excited about the Arsenal project since they first approached him.
In the coming days, he will undergo his medical examination and will likely join his new teammates in the United States for pre-season training.
Just Arsenal Opinion
Calafiori has been a player we wanted to sign the most this summer, and it is refreshing that we have finally reached an agreement to add him to our squad.