Zandvoort is hoping to welcome a full house of spectators to its first Dutch GP in September.
Formula 1 has just announced that Portimao will join the 2021 schedule in May - with F1 CEO Stefano Domenicali declaring that he hopes spectators will be there.
"We hope to welcome fans to Portimao again this season in a safe way and are working with the promoter on the details of that plan," he said.
As for Zandvoort, that race was cancelled last year as organisers opted against a 'ghost race' format amid the pandemic.
Now, circuit boss Robert van Overdijk is hoping for as normal a 2021 event as possible.
"Last year we really had a hard time so we had to take certain measures," he told Ziggo Sport. "The calendar for this season gives us hope.
"So we are preparing for the race as though 105,000 people will come to the circuit every day. At the moment we don't know how many spectators will be allowed, but we must be ready for a full house.
"One way or another, the grand prix will take place," van Overdijk added.
