Spain's Guardia Civil said a total of 13 people had been arrested in Barcelona, Madrid and Malaga.
The head of the smuggling operation, a British national, fled to Dubai after an attempted arrest in Spain and was continuing to direct operations from there, it said in a statement.
The cocaine was imported from Panama in central America and his supplier, a Panamanian, also lived in Dubai, it said.
Belgian prosecutors said the investigation had already led to raids in Antwerp in August, in which local media said around 900,000 euros had been seized.