Wembley received permission from the British government on Monday to admit a minimum of 40,000 spectators to four European Championship matches.
These include the semi-finals and the final of the European tournament.
Wembley is almost half filled with that number.
According to British media, 45,000 fans would be welcome at the duels.
The current corona measures in Great Britain were extended by four weeks on Monday, but an exception will be made for some sporting events - including the European Championship and Wimbledon.
At the moment, the three group matches of England are still allowed to be 22,500 fans.
England won the first European Championship match against Croatia 1-0 on Sunday.
Spectators who want to visit Wembley still have to show a vaccination certificate or a (negative) corona test.
The test must not be older than 48 hours, the (last) vaccination must have been made at least two weeks earlier.
In Amsterdam, sixteen thousand spectators may be present in the Johan Cruijff ArenA during the European Championship.