The number of migrants who died or went missing was twice as high as in the previous year, the UN's refugee agency said.
More than 3,000 migrants died or went missing while trying to reach Europe by sea, the UN's refugee agency (UNHCR) has said.
The number of deaths (3,077) is twice as many as in 2020, according to the latest report released on Friday.
The UN has called for governments to develop "alternatives" to the dangerous sea routes that asylum seekers desperately use to reach European land.
"Of this total, 1,924 people were reported dead or missing on the central and western Mediterranean routes," UNHCR spokesperson Shabia Mantoo said.
"Another 1,153 died or went missing on the sea route from northwest Africa to the Canary Islands," she added.
By the end of 2020, the UN agency had recorded 1,544 migrant deaths for both sea routes.
Meanwhile, officials have warned that at least 478 people have already died or gone missing while trying to reach Europe in 2022.
According to the UN High Commissioner for Refugees, the COVID-19 pandemic and subsequent border closures have had an impact on migration flows, with many refugees and migrants turning to smugglers to try to reach Europe.
More than 53,000 people arrived by sea in Italy last year, as well as over 23,000 people at Spain's Canary Islands. There was also a 61 percent increase in departures by sea from Tunisia last year compared to 2020, and 150 percent from Libya.
Most sea crossings are made in crowded inflatable boats in poor condition that can deflate or capsize, UNHCR said.
"The sea journey from West African coastal states such as Senegal and Mauritania to the Canary Islands is long and perilous and can take up to 10 days," Mantoo told a regular press briefing in Geneva.
"Many boats have gone off course or disappeared without a trace in these waters," she added.
The central Mediterranean is the world's deadliest migration route, with more than 17,000 deaths and disappearances recorded since 2014 by the International Organization for Migration (IOM).
UNHCR says land routes can also be very dangerous for migrants and estimates that even more people may have died crossing the Sahara Desert or when held in captivity and abused by traffickers or smugglers.
On Friday, the UN launched a fresh appeal for more than €155 million to help protect migrants and refugees trying to reach Europe.