The date is slightly later than predicted by UBS chief executive Sergio Ermotti, who had said that the merger could be finalised by late May or early June.
The bank had initially foreseen a late-June closing date.
Switzerland's biggest bank agreed to buy Credit Suisse on March 19 for three billion Swiss francs ($3.25 billion), under strong pressure from the government its rival from collapsing.
"UBS expects to complete the acquisition of Credit Suisse as early as 12 June 2023. At that time, Credit Suisse Group AG will be merged into UBS Group AG," UBS said in a statement.
Upon completion of the merger, Credit Suisse shares and American Depositary Shares (ADS) will be delisted from the Swiss stock exchange and the New York Stock Exchange, the statement said.
Ermotti has said the takeover will create a superbank in charge of $5 trillion of invested assets.