Cagliari's old city is compact and largely pedestrianised — the Castello quarter, Marina, and Stampace can all be covered on foot. The main sights in Castello require a climb; you can take the lift from Piazza Costituzione at the base of the Bastione di Saint Remy for the easiest ascent.
The city has an expanding light rail network (MetroCagliari) and a comprehensive bus system run by CTM. For Poetto beach, line P (beach bus) runs in summer from the centre. For wider exploration of Sardinia, renting a car is strongly recommended — the island's best sights are spread across a large area and public transport is infrequent outside the main towns.