King William II of Sicily ask for Joannna's hand in Marriage in 1176. This union was arranged and confirmed on 20 May. John of Oxford (bishop of Norwich and her uncle)and Hamelin de Warenne (5th Earl of Surrey) escorted Joan to Sicily. They set sail on 27 August and arrived safely on 13 Feb 1177 in spite of the hazardous voyage. Representatives of the Kingdom of Sicily, Alfano (Archbishop of Capua) and Richard Palmer (Bishop of Syracuse), met Joanna's entourage.

Joanna married William II of Sicily and was crowned Queen of Sicily at Palermo Cathedral. They had one son, Bohemond, born in 1181 and who died in infancy.

William died in 1189. The new King Tancred of Sicily kept Joanna a prisoner until her brother Richard I of England arrived in Italy in 1190, on the way to the Holy Land for the Third Crusade, demanded her return, along with every penny of her dowry. Tancred did not like these demands and refused to meet them. Richard then seized a monastery and the castle of La Bagnara. He remained in Italy and spent the winter there while he attacked and subdued the city of Messina. Finally, Tancred agreed to the terms and sent Joanna's dowry.

Eleanor of Aquitaine arrived in Messina in March 1191 with Richard's bride, Berengaria of Navarre. When Eleanor returned to England, she left Berengaria in Joanna's care. Richard postponed his wedding and he put his bride and sister on and ship, he on another, and they set sail. A bad storm hit two days later destroying several ships including Joanna's and Berengaria's ship which was blown off course. Richard landed safely in Crete, however, the princesses were stranded near Cyprus. Richard's fleet suddenly appeared near Cyprus where Isaac Comnenus, the self-appointed despot of Cyprus, was about to capture them. Richard them, but the despot made off with Richard's treasure. Richard pursued, captured Isaac and threw him into a dungeon. Joan and Berengaria were sent on to Acre.

Richard never hesitated to use Joanna as a bargain chip for his political gain even tho she was his favorite sister. He tried to get her to marry Al-Adil which would make them joint rulers. However, Joanna refused to marry a Muslim and Al-Adil refused to marry a Christian. King Philip II of France wanted to marry her, but this was not possible on grounds of infinity because Philip's father Louis VII had been married to Joanna's mother.

Raimond VI of Toulouse received Joanna's hand in marriage in October 1196 along with Quercy and the Agenais as her dowry. She was his fourth wife. Raimond's first wife died and he divorced the second and third wife. He married two more times after Joanna fled from him. Raimond treated her roughly and she began to fear him and his knights. She was pregnant with their third child when she was left alone during the rebellion in which the lords of Saint-Félix-de-Caraman were prominent. She tried to sieze their castle but was treated with treachery. She escaped and traveled north with hoping for the protection of her brother. She found him dead at Chalus. Her mother Queen Eleanor's court in Rouen offered refuge and care.