EU border security chiefs Frontex said the improved figures were down to a combination of tighter security on Balkans routes, greater control of boats leaving Libya and the stepping up of returns of failed asylum seekers.
Frontex had helped deport some 14,000 people last year.
However some routes into Europe, especially the southern borders in the Mediterranean will remain “at a very high level” in 2018, the head of EU’s border and coast guard agency Frontex said.
Some 119,000 Africans were arrested trying to enter the EU last year on migrant boats departing from Libya, more than 42,000 from Turkey to Greece and another 23,000 from Algeria and Morocco to Spain.
He said: “The western Mediterranean route is under scrutiny. While the number of migrants on the Libya-Italy route has dropped significantly since Libya – encouraged by the EU – began to block departures from its shores last July, illegal crossings into Spain more than doubled from below 10,000 in 2016.”
The fact that people smugglers operating on the western Mediterranean route have started using more “solid” rubber boats to ferry migrants could explain the sharp increase, Mr Leggeri said.
Since the 2016 EU-Turkey refugee deal mostly halted the flow of Syrian migrants into Greece, African nationals made up nearly two-thirds of the 205,000 people caught trying to cross into Europe illegally last year, Frontex said.
In 2017, Syrians and Nigerians each accounted for nine per cent of overall arrivals, followed by migrants from Ivory Coast, Guinea and Morocco.
Domestic issues in Morocco, which is the main transit country for Spain-bound migrants, led to an increase in departures from the North African country’s western coast in particular, Frontex added.
But despite the increased migratory pressure on the bloc’s southern borders, Frontex said that there had been a sharp decline in the number of detected illegal crossings in 2017.
“Overall” illegal immigration to Europe fell by 60 per cent last year.
Mr Leggeri said: 204,219 people crossed an EU border illegally in 2017, compared to 511,074 in 2016 and 1,8 million in 2015.
The border chief explained that the EU was stepping up returns of failed asylum seekers, underlining that Frontex had helped deport some 14,000 people last year.
Frontex, however, warned of a possible increase in the use of fake travel documents and undocumented crossings across the EU as member states move to tighten their asylum laws and border controls, saying that an increasing number of people could seek to hide in lorries, cars or cargo trains.