The curfew will apply from May 23-May 27 following the end of the fasting month of Ramadan.
Saudi Arabia had earlier imposed 24-hour curfews on most towns and cities but eased them for the start of Ramadan. It did not loosen the full isolation lockdowns implemented in some areas with high numbers of coronavirus infections.
The kingdom has so far recorded 42,925 cases of the COVID-19 respiratory disease and 264 deaths.
These are the highest numbers in the six-member Gulf Cooperation Council (GCC), which together have recorded more than 107,000 cases and 582 deaths.