That is more than triple the number who reached Spain at the same time previous year, according to Joel Millman, a senior IOM spokesman, and already more than the total arrivals in 2016.
Tourists and sun worshipers lounging on a Spanish beach were stunned when an inflatable dingy full of migrants landed on the shore.
The International Organisation for Migration said it had found the shallow graves of 29 migrants on a beach in the southern province of Shabwa after they had been buried by survivors.
Some 40 sub-Saharan Africans arrived by boat on a southern Spanish beach recently and scattered among startled sunbathers and a day later some 700 others tried unsuccessfully to storm the border crossing between Spain's North African enclave of Ceuta and Morocco.
"It's possible that Spain will outperform Greece this year", Millman said. Overall, the numbers of migrants crossing the Mediterranean have dropped dramatically this year, mostly because of the rapid decline in the number arriving in places like Greece and Cyprus. The IOM reports that 97,000 migrants have gotten to Italy by boat so far this year, slightly down from the 100,000 who did so during the same period last year.
He said many people taking the long route towards Europe were from west African countries like Senegal, Gambia, Guinea or Ivory Coast. The country has to be prepared for an increase of arrivals, increase of asylum-seekers.
"We assume that some of the change is due to the fact that the route is considered a safe route up to the coast through Morocco", Millman said.
"The use of these playthings is troubling. one large wave and they can flip over and leave people in danger", the Frontex spokesman told the Thomson Reuters Foundation by phone.
The good weather over the past few weeks seems to have led to a sudden increase in the number of migrants arriving in Spain.
Both the cities have the EU's only land borders with Africa and so are easy entry points for migrants wanting to get to Europe.