The capital of Sardinia is CAGLIARI, an 8-letter word. CAGLIARI is the largest city on the Italian island of Sardinia and is located in the south of the island. It is a major port city and is known for its vibrant culture, beautiful beaches, and archaeological sites. CAGLIARI has been inhabited since pre-Roman times and was an important trading post during the Middle Ages. Today, it is a popular tourist destination and is home to many historical monuments and attractions.