Under the new government regulations, introduced on Saturday, open-air stadiums are able to admit 50 percent of their capacity, up from 25 percent under previous regulations.
Spectators are obliged to take every second seat, or keep a distance of 1,5 meter, while covering their faces with masks.
Poland reopened outdoor sports areas and allowed football matches to be played behind closed doors in late May.
Culture and entertainment venues as well as indoor sports facilities were allowed to restart their operations from June 6.
Polish football and speedway stadiums reopened to spectators at 25 percent capacity on June 19.
A total of 42,038 people have tested positive for the coronavirus in Poland, with 1,655 deaths from the COVID-19 respiratory disease so far, officials said on Friday.