The distance between the Sardinian cities of Chia and Cagliari is just 33 miles (53 km), making the trip from one city to the other fairly easy. The best way to get from Cagliari is by renting a car, though it's also easy to hire a private driver if you'd prefer to avoid navigating and parking in a new city.
You can also take a bus, but they do not run frequently and may not coincide with your plans. However, a bus will get you to Cagliari in under two hours.
If you're planning your trip to Sardinia, make sure to check this ultimate guide to the island. For a planned itinerary that includes plenty of easy hikes around the island, tours of wineries, visits to ancient ruins, and more, check out this 12-day trip.
By Rental Car or Private Transfer
Duration: 1 hour, more with stops and traffic
Driving is the most convenient transit option for this journey. Private transfers are widely available in Sardinia, so this is the most convenient option. If you rent a car, be sure to choose a small car as the roads can be quite small in the cities.
You'll take the SS195—otherwise known as the "Sulcitana"—all the way to your destination. Be sure you don't choose the route that takes you through a segment of the SS130 as it's far less scenic and takes you through large industrial areas.
About 11 miles (18km) into your journey, you'll come to the ancient Phoenician city of Nora, which is a highly recommended stop. Once you get closer to Cagliari, you'll appear to be floating on the water as you cross a bridge over the Stagno di Cagliari Lagoon and the Meditteranean Sea.
Driving across the SS195 yourself is not particularly challenging, but be sure to pay attention to the local customs and rules of the road. If you take your own car, the best solution for parking is a pay-by-the-hour garage as central street parking may be difficult to come across. Make sure to watch out for ZTL zones (restricted driving areas) in the city center that restrict access for non-resident vehicles.
Duration: 1.5 hours
For this option, you'll have to take the 129C Line operated by the regional bus company ARST. You can choose to depart from three different stations—Chia Bar Tabacchi, Chia Market Sirio or Chia Bivio—and the destination in Cagliari will be the Main Bus Station. Make sure to check the schedule in advance as buses between Chia and Cagliari run every two to three hours.
You can purchase bus tickets at any tabaccheria (tobacco store). You can also purchase your ticket in advance online, but the website is only available in Italian.