Even if you have a car available, you might want to take a bike tour. Ask at any tourist office for a map of the island's more than 190km (120 miles) of bicycle trails, and divide this tour into several days, hitting the highlights mentioned below at your own pace.
The tour begins at Rønne, but you could join in at almost any point; basically, the route goes counterclockwise around the island's periphery. Be aware that Bornholm's highways do not have route numbers; even though some maps show the main east-west artery as Route 38, local residents call it "the road to Nexø."
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.