Now the owner of PT, the company confirmed its decision to French media earlier this week, following representations from the local competition authority.
A number of interested parties have already come forward, but no immediate deal is on the table.
Altice founding partner Armando Pereira said he intended to invest an annual €150 million over the next two to three years to build a fibre-optic network across Portugal.
Cabovisão was sold by Cogeco Cable to Altice for €45 million in March 2012 in a move that marked the end of the Canadian company’s expansion into Europe.
Six years earlier, it had acquired the Portuguese operator for $660 million.