Spain has entered a new state of emergency, imposing local nighttime curfews, and banning some travel between regions.
Prime Minister Pedro Sanchez warned the country was facing an "extreme" situation and called it the most serious health crisis in the last century.
In tourist hotspots such as Barcelona and the surrounding areas, restaurants and other establishments have to close by 9 p.m., an hour before the curfew starts at 10 p.m.
Police were seen patrolling the city before the new rules took effect on Sunday (October 25). Locals appeared to be complying with them, as usually busy streets emptied.
Spain imposed one of the toughest lockdowns earlier this year and then relaxed curbs over the summer.
In Italy, similar measures have come into force, with dining areas and bars ordered to close even earlier, from 6 p.m.
Cinemas and gyms have also been ordered to shut down as part of local curfews in several regions.
There were street clashes with small groups of protestors over the weekend and angry criticism from restaurant owners and business groups about the impact of the measures.
Prime Minister Giuseppe Conte said the measures were aimed at protecting both public health and the economy.
He added that if the situation could be brought under control in the next few weeks, he had hopes for Italians to have a "serene" Christmas.