Fifty-four-year-old grandmother Annie Richards from Neath is in a stable condition in hospital after surgery following the attack on Wednesday.
The initial operation to amputate her injured arm by surgeons in the town of Villajoyosa was described as "successful" by a spokesman at the British Embassy in Madrid.
Mrs Richards, who was visiting the El Arca Safari Park near Alicante with her sister, is understood to have been invited to put her hand in the lioness's mouth at a tourist show.
Hospital porter
But the show went wrong when the lioness - named Marta - turned on the tourist and ravaged her arm..
The animal mauled the woman's hand and eventually ripped her arm off from the elbow.
The limb was not recovered because other lions pounced on it, the Spanish news agency Efe reported.
Mrs Richards' husband Jimmy, a hospital porter, and her son Michael, 32, and daughter Amanda, who is 30, were told of the accident last night.
Bedside
Arrangements by the tour operator were being made to fly the family to Spain.
Mrs Richards is recovering in a hospital in Benidorm after the surgery to amputate her injured arm.
Her sister Carol Jones, from Bryncoch, south Wales, is at Mrs Richards' bedside in the hospital.
A spokesman at the safari park in the town of Benimantell, which specialises in endangered species, said it is the first time they have had any kind of accident there.
The spokesman said he had worked there 20 years and had never known an accident.