Majorca has been hit by killer flash floods.
Their vehicle was swept away by a torrent of water near the coastal resort of S'Illot.
A spokeswoman with the regional emergency service said two British nationals and a Dutch woman were among the victims, but she couldn't confirm whether six more people were still missing at midday as local media reported.
Sant Llorenc, which is about 60 kilometers (40 miles) east of Mallorca's capital, Palma, is where a dry creek overflowed amid heavy downpours, creating a strong current of water and mud that buried cars and tore trees along the way, according to witness accounts.
Witnesses told how they had minutes to get to safety as the water levels rose. Among the dead are two Britons who were thought to have been caught in a flash flood while travelling in a taxi.
At least nine people are believed to have died in torrential rainstorms on the island of Majorca.
The auto was submerged and on its side at the mouth of the torrent in S'Illot on Wednesday.
Military divers found the couple's bodies still inside, while Mr Sillero was later found lifeless nearby, the paper said.
The Foreign Office said in a statement: "We are in contact with the Spanish authorities responding to flooding in Majorca, and urgently seeking updates from them".
Diario de Mallorca reported that the bodies of an 81-year-old man and 83-year-old woman were among the first to be found on Tuesday.
Hundreds of displaced residents are seeking shelter in emergency relief centres, while soldiers have been sent to assist the rescue effort, Spanish authorities said.
The player invited locals to take shelter at his tennis academy in nearby Manacor, and then donned wellington boots to join other volunteers.
Spain's Prime Minister, Pedro Sanchez, has visited the island today and said in a Tweet: " I want to convey our gratitude to the emergency services, who work tirelessly to serve all those affected".
Sanchez will be flying to the area later Wednesday, his office said.