A record 181,000 migrants reached the shores of Italy in 2016 on flimsy boats from northern Africa.
This was a major increase of 20% over 2015, EU border agency Frontex said on Friday.
The sea route to Italy was the only path to Europe which saw a rise in migrant numbers last year.
Elsewhere overall refugee arrivals on the two main sea routes fell dramatically last year, plunging by nearly two-thirds from 2015. The reported total was 364,000.
Frontex said the decline was due in part to the EU border deal with Turkey, effective from March 2016, which helped reduce the number of migrants reaching Greece.
"The number of migrants detected on Greece's islands in the eastern Aegean and its mainland dropped by 79% to 182,500," Frontex said preliminary estimates showed.
The sudden arrival of more than one million migrants last year, triggered in large part by the desperate situation in Syria, created the most severe migration crisis in Europe since WWII.
