The measure will be approved at Tuesday's cabinet meeting, Health Minister Carolina Darias told Cadena Ser radio.
Spain first imposed obligatory mask-wearing outdoors in May 2020, but lifted it in June last year, although wearing a face covering was still required for indoor public spaces.
"For several weeks now, we have seen how all the indicators are improving, day-by-day," Darias said, referring to the incidence rate and pressure on hospitals.
In recent weeks, many of Spain's regions have moved to ease restrictions that were tightened in the face of Omicron, with the northeastern Catalonia region dropping as ineffective the requirement to show a Covid passport to enter restaurants, bars and gyms.
The region has also dropped a nighttime curfew along with capacity restrictions in bars and restaurants, and will reopen its nightlife venues on February 11.
Despite high levels of vaccination in Spain, Covid cases exploded in Spain over the Christmas holidays, giving it one of Europe's highest incidence rates, although that has now fallen.
So far, Spain has registered some 10.2 million cases of the virus, and 94,000 deaths.