Manchester United sign De Ligt and Mazraoui after selling Wan-Bissaka to complete defensive shake-up
The 25-year-old De Ligt agreed to a five-year deal, with the option to extend for a further year.
The 26-year-old Mazraoui, who can play as a right back or left back, has a contract until June 2028, also with the option to extend for a further year.
No transfer fees were announced but British media reported United was paying 60 million pounds ($77 million) for Mazraoui and De Ligt.
United earlier Tuesday sold Aaron Wan-Bissaka to Premier League rival West Ham for a reported fee of 15 million pounds ($19 million) to end a five-year spell at United. One of the best one-on-one defenders in the English game, Wan-Bissaka will compete with Vladimir Coufal for the right-back spot at West Ham. Wan-Bissaka returns to London, having started his career at Crystal Palace.