The city centre is compact and walkable — the main museums, the plaza, and the cathedral are all within easy reach on foot. For the sites further out, you will need transport.
Taxis are plentiful and inexpensive within the city. Colectivos (shared taxis running fixed routes) cover most city neighbourhoods for a flat fare. Car rental is available at the airport and in the city centre, which is necessary if you plan to visit the national parks — the roads to Nevado Tres Cruces and Ojos del Salado require a 4WD vehicle and you cannot reach them by public transport.
A rental car also opens up Bahía Inglesa and Caldera to the west, and the San José mine memorial to the north. Organised tours from Copiapó cover the main desert destinations; several agencies near the plaza offer full-day trips to the national parks and the coast.