Land at Olbia airport, skip the coastal road, and reach the Costa Smeralda by sea in about 35 minutes. Private transfer straight from the port, no rental car, no traffic.
The SP73/SS125 coastal road from Olbia to the Costa Smeralda is notoriously congested in July–August, and airport taxis or rental cars add waiting time on top of the drive.
A private boat leaves straight from Olbia port, harbour to harbour, in about 35 minutes — no road, no traffic, no rental car to arrange.