Sharai Mawera died yesterday after the beast pounced as she enjoyed a romantic al fresco moment with her unnamed partner.
The My Zimbabwe news website reported that the predator attacked the couple at a secluded spot in the bush near the northern town of Kariba.
Ms Mawera's boyfriend, who has not been identified, is believed to have jumped up and fled in the nude when the lion lunged forward
A source told the newspaper the young woman died at the scene.
He said: "Unfortunately the woman was mauled to death by the lion, but her boyfriend managed to escape naked."
The friend said: "He is a fisherman and he used to often meet at the same spot with his girlfriend, who is now deceased.
"The two were romping when the incident occurred. The lion came from behind and roared.
"The guy managed to escape before stopping at a distance where he witnessed his companion being attacked.
"He later rushed to the road seeking help."
My Zimbabwe reported that the terrified man managed to raise the alarm.
Local police and armed rangers from the Zimbabwe Parks and Wildlife Management Authority rushed to the scene.
The source said: "Cops and officers attended the scene and fired a single shot before getting to the spot.
"The woman had already been killed. She had bloody bruises all over her body. Her neck and tummy had been mauled."
Rangers launched a hunt for the lion following the tragedy, amid concern the same animal may have killed a local man who disappeared at the weekend.
The remains of the victim were found yesterday on the outskirts of the town, which lies near the Zambezi river.