Karratha Airport (KTA) has multiple daily flights to Perth (around 1 hour 45 minutes), mostly operated by Qantas and Virgin Australia. Given the distances involved — Karratha is about 1,500 kilometres north of Perth — flying is by far the most practical option. Driving from Perth on the North West Coastal Highway takes 15–17 hours and should be broken into at least two stages.
The Greyhound bus service covers the route from Perth but takes 20+ hours and is not a comfortable option for most visitors. A hire car is essential once you arrive — Karratha has no public transport worth speaking of.