Leo, who drew the ire of Donald Trump last year after calling the U.S. president's hardline anti-immigration policies inhumane, also urged the world to become "more human" and to help those fleeing war and poverty.
During a day trip to Lampedusa, a gateway for migrants risking dangerous Mediterranean crossings into Europe from Africa, the pope urged European leaders to do more to assist arrivals, which have topped 7,000 this year.
Separately, in an appeal sent to the U.S. for its landmark anniversary, Leo said the Catholic value of defending life includes "welcoming, protecting and assisting immigrants."
"To receive (immigrants) with compassion and generosity is not only an act of charity, but also a recognition of the dignity that belongs to every human person," he told the United States.
POPE SAYS HE WANTS TO ACCOMPANY, SUPPORT LAMPEDUSANS
Lampedusa, which lies between Tunisia, Malta and Sicily, sits on one of the world's deadliest migration routes. Many migrants arrive after crossing the Mediterranean in overcrowded boats and makeshift vessels.
The visit echoed that of Pope Francis, who made Lampedusa the destination of his first trip outside Rome after becoming pope in 2013.
Among those gathered near Italy's southernmost port to see the pope were newly arrived migrants, Italian Coast Guard search-and-rescue officials and aid groups.
Leo told them he had come to show that the pope "continues to accompany you, support you and encourage you".
The pope also called on European leaders to tackle migration "in a comprehensive manner, integrating immediate relief efforts into a long-term strategic plan capable of receiving, protecting, supporting and integrating migrants".
He also called on them to help improve conditions in migrants' home countries so that fewer people feel compelled to leave.
"The pope's visit speaks to every one of us," Kandeh Abdourahman, a migrant who arrived in Lampedusa in 2015 after travelling across five African countries, the Sahara Desert and the Mediterranean, told Reuters.
It is "a reminder that our stories are seen, that welcome is not just a word but an act of humanity," said Abdourahman, now a cultural mediator with the International Rescue Committee.
A total of 14,464 migrants have arrived in Italy by sea so far this year, according to U.N. Refugee Agency data provided to Reuters, with more than half landing in Lampedusa. The figure exceeds the island's resident population of about 6,000.
More than 1,400 people have died or gone missing while attempting to cross the Mediterranean this year, including 28 children, according to the U.N.'s International Organization for Migration.
VISIT CARRIES 'MORAL AND POLITICAL WEIGHT'
Since becoming pope in May 2025, Leo has made support for migrants a central theme of his papacy. Last month, he warned that history would judge harshly leaders who mistreat immigrants.
In his first major address to the U.S. on Friday, he praised the country's history of welcoming immigrants and urged Americans to uphold the ideals set out in the Declaration of Independence.
Arriving in Lampedusa shortly before 9 a.m. (0700 GMT) on Saturday, Leo laid flowers at a local cemetery on the graves of migrants who died attempting the Mediterranean crossing.
He also visited the "Door of Europe," an art installation on Italy's southernmost beach dedicated to migrants, walking through the structure towards the Mediterranean amid strong winds.
Tareke Brhane, an Eritrean-born migrant rights advocate who briefly greeted Leo, said he was overcome with feelings from the visit.
"I got chills from the emotion," said Brhane, president of the October 3rd Committee, an Italian non-profit established after a 2013 shipwreck in Lampedusa killed 368 migrants.
He said he hoped the pope's presence would push European leaders to create a registry identifying migrants lost at sea.
Vatican officials said the pope wanted to underline his message of support for migrants and deliberately timed the visit to coincide with the July 4 U.S. Independence Day holiday.
"Pope Leo XIV's presence sends a clear message at a time when the global political debate on migration is often framed around borders and deterrence rather than protection and shared responsibility," Anna Leer, an official with the U.N. Refugee Agency, told Reuters.
"Every act of witness to the humanity of those who flee violence, persecution and conflict carries moral and political weight," she said.
