When the young female appeared in shallow waters off a beach in Mojacar last Friday after becoming separated from its mother, it was crowded by dozens of bathers who rushed to touch it and photograph themselves with it.
Some images even show small children grabbing at the dolphin and accidentally covering the blowhole on the top of its head.
By the time marine animal rescuers had arrived at the beach -15 minutes after being called immediately the stranded dolphin was spotted - it was too late and the animal had perished.
"Ceteceans are very sensitive animals that are highly susceptible to stress. Crowding round to touch them and take photos provokes shock and greatly accelerates cardiorespiratory failure. Which is exactly what happened in this case," said a statement on the Facebook page of Equinac, the marine animal rescue service.
The NGO acknowledged that the baby dolphin – which was so young that it was still milk-fed by its mother - had slim chances of survival.
"The young dolphin was vulnerable because it was separated from its mother either through sickness or loss and it could not survive long without her," the statement said.
"But touching it and crowding around it for photographs caused enormous stress and hastened its death."
A spokesman told Spanish news agency Efe: "We may not have succeeded in rescuing her, but we would have tried."
The group reminded people who come across a stranded marine animal, such as a dolphin or turtle, to immediately call 112 and then keep their distance from the stricken creature until experts arrive.