Young Moroccan drowns trying to reach Spain's Ceuta
The incident occurred on Thursday evening, and the body was discovered in the water near Tarajal beach at 9:15 pm (7:15 pm GMT).
The victim's age was not immediately clear but a police spokesman said he was a "young man" who "seemed like an adult".
They also rescued another Moroccan who was with him.
Although it is only a 200-metre (650-foot) swim from the Moroccan side to Tarajal beach in southern Ceuta, migrants often attempt the crossing fully clothed, which can be exhausting and dangerous.
Forensic experts would carry out an autopsy to determine the victim's age, the police said.
Spain's two tiny enclaves of Ceuta and Melilla have Europe's only land border with Africa, making them a magnet for migrants desperate to escape grinding poverty and hunger.
Both coastal territories are protected by fences fortified with barbed wire, video cameras and watchtowers.
In mid-May, Spain was caught off guard when more than 10,000 people swam or used small inflatable boats to cross into Ceuta as the Moroccan border forces looked the other way.
The influx came during a diplomatic crisis over Western Sahara, which has long pushed for independence from Morocco.
Spain had angered Morocco by allowing a separatist leader in for hospital treatment, and the migrant surge in Ceuta was widely seen as a punitive move by Rabat.
Most were returned to Morocco soon after they arrived but at the end of July, some 2,500 remained in Ceuta, including hundreds of unaccompanied minors, according to the authorities.