The 55-year-old Portuguese is accused of committing tax fraud in 2011 and 2012, prosecutors said last year.
He has reportedly accepted to pay a fine corresponding to 60 percent of the amount he allegedly hid from the taxman and to a one-year prison sentence that should be commuted into another fine, the newspaper said.
That should come to a total of more than five million euros, it added.
The deal reached with prosecutors and the Spanish taxman has not yet been submitted to the court investigating the case, according to El Mundo.
Mourinho is the latest in a long list of football players and other personalities in the industry to be accused of tax fraud in Spain on income related to image rights in the past few years.