Organizers invited young Portuguese Catholics last November to prepare for World Youth Day by taking part in a two-day mission.
In light of the pandemic, they asked youngsters to take part in the mission by calling someone who lives alone, speaking to distant family members via the internet, volunteering with local charities, or undertaking acts of service in their parishes.
Pope Francis announced that Lisbon would host the global Catholic gathering of young people at the closing Mass of the last international World Youth Day in Panama City in January 2019.
The city of 505,000 people is around 75 miles from Fatima, one of the world's most popular Marian pilgrimage sites.

Organizers launched the WYD Lisbon 2023 website and official logo last October. The logo, featuring the Blessed Virgin Mary in front of a cross, in the colors of Portugal's flag, was selected in an international contest.
In January, organizers unveiled the event's official theme song. The song, entitled "Há Pressa no Ar" in Portuguese ("There's a rush in the air"), invites young people to identify themselves with the Virgin Mary.
To young people in the United States wondering if it will be safe to travel to Portugal by 2023, Bishop Aguiar said: "If it will not be safe to travel to Lisbon in 2023, we will not invite young people to come. Life and security are the most important."
The Portuguese Episcopal Conference suspended public worship last month due to the "extreme gravity" of the coronavirus crisis in the country.
Asked if there was anything he would like to add, the bishop said: "God bless America!"
Luke Coppen is Europe editor of the Catholic News Agency. From 2004 to 2020, he edited the U.K'.s Catholic Herald. He is based in England.