The Euro 2020 semi-finals and final will be played in front of 40,000 fans at Wembley, while a capacity crowd will witness the Wimbledon finals as part of a series of new pilot events in England.
British Prime Minister Boris Johnson on Monday announced a four-week delay in England to the full lifting of coronavirus restrictions -- which were due to end on June 21 -- because of a surge in infections caused by the Delta variant.
However, the final four matches at Wembley of the European Championship will be able to nearly double the crowd that saw England win their opening match against Croatia 1-0 on Sunday.
England will also face Scotland and the Czech Republic in front of 25 percent capacity at Wembley in the next week.
But a last 16 match on June 29, plus the semi-finals and final in July, will be staged in front of the largest crowd in the UK for more than 15 months.
Wimbledon will be allowed to operate at 50 percent capacity during the two weeks of the tournament, which was cancelled last year due to Covid restrictions.
The women's final on July 10 and men's showpiece the following day will be watched by a full 15,000 crowd on Centre Court.
"We want to gather further evidence on how we can open up all big events safely, and for good," Culture Secretary Oliver Dowden said.
"The expansion of trials of the NHS app and lateral-flow testing will mean that bigger crowds will be able to attend a limited number of major sporting and cultural events early this summer as part of our events research programme.
"In the next few weeks this means more fans enjoying the Euros and Wimbledon, and some of our biggest cultural and sports events."
England's group games at Euro 2020 had already been included on the government's extended events research programme and will continue to be played in front of crowds of 22,500.
Ticket holders for matches at Wembley have to provide proof of full vaccination or a recent negative Covid-19 test result.
Wimbledon welcomed Monday's developments and said it would announce further details on Wednesday regarding spectator capacity and covid protocols for the Championships.
"We are continuing to work closely with the government to finalise the details of our participation in the event research programme, including the requirements for Covid-status certification for spectators," a statement read.