There will be capacity crowds for the Wimbledon finals next month and around 45,000 people are set to be allowed into Wembley for the Euro 2020 semi-finals and final.
Prime Minister Boris Johnson on Monday announced a four-week delay in lifting coronavirus lockdown restrictions in England to July 19 due to rising cases of the Delta variant.
However, Wimbledon and the European Championship are being treated as test events, so there is set to be a full house of 15,000 on Centre Court for the championship matches on the weekend of July 10-11.
The grass-court grand slam will be the first outdoor sporting event to have a capacity crowd since the start of the pandemic.
When the tournament, which was not staged last year due to the COVID-19 crisis, starts on June 28 it will be at 50 per cent capacity.
A statement from the All England Club said: "We are pleased to have worked closely with the government, public health bodies, and our local authority in Merton, to confirm that, as part of this next phase of pilot events, The Championships 2021 will begin on Monday 28 June with 50 per cent capacity across the Grounds, building to full capacity crowds of 15,000 on Centre Court for the finals weekend.
"This will enable us to fulfil our aspiration of staging the best Wimbledon possible within the current circumstances, with the health and safety of all those who make Wimbledon happen - our guests, competitors, members, staff, media, officials, local residents, and partners - remaining our highest priority."
Crowds for England's first two Euro 2020 group games at Wembley have been capped at 22,500, but that figure is expected to be doubled so the stadium is half full for the semi-finals and final.
The semi-finals will be staged on July 6 and 7, with the final held on July 11.
Culture Secretary Oliver Dowden said: "We want to gather further evidence on how we can open up all big events safely, and for good.
"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."