Migrants don't usually disembark on Spanish beaches but it has happened before, especially near the cities Melilla and Ceuta, which border Morocco.
Earlier this year, it emerged the number of migrants reaching Malaga in the first six months of 2017 - 749 people - had nearly equalled then umber for the whole of the previous year.
Local newspaper Diario De Cadiz reports that many of those on board quickly changed their clothing to evade the police, who carried out searches to apprehend the suspected illegal migrants.
The numbers have dropped significantly since then, in a large part due to a deal the European Union struck with Turkey to keep migrants there. The pace has quickened so rapidly in recent months that some experts think the country could overtake Greece in the number of newcomers arriving by boat this year.
Experts say it's hard to pinpoint why the water route to Spain via Morocco has become a preferred option for some migrants.
According to the EU's Frontex border agency, 7,500 immigrants made the crossing to Spain in the first three months of the year, compared with 3,600 in the same period last year.
"It's possible that Spain will outperform Greece this year", Millman told AFP.
Italy still far surpasses both Spain and Greece in the number of migrants arriving on its shores in 2017.
"People are talking about going to Spain".
Before waves of refugees and migrants started pouring into Europe via the Mediterranean two years ago, simple wooden boats arrived in Spain regularly starting in the early 1990s. It seems like it is safer to go through Morocco to Spain than through Libya.
IOM figures showed that 121 migrant deaths were registered along the Spanish route in 2017, while Italy saw 96,861 arrivals in the same period, with 2,242 deaths registered on that route.
Inigo Vila, in charge of emergencies for the Red Cross in Spain, said the organisation had reinforced the number of people working on the coast in southern Andalusia and in Ceuta to help migrants when they make landfall.