Given that there is no public transport in the valley, the best way to get to Adonis Valley if you do not have your own transportation is by taking a taxi from Byblos. Expect to pay between 20,000 and 30,000 LBP depending to where in the valley you are heading. Duration: 30 - 60 min.
To reach the steep mountain road running north and parallel to the Ibrahim River by car, get on the coastal highway, whether from Beirut, Jounieh or Byblos, and take exit just north of Nahr Ibrahim in the direction of Qartaba. Note that the road from there is winding and - at the time of writing - full of potholes and road constructions.
To reach the beautiful road running through the valley south of Nahr Ibrahim by car, get on the seaside road just north of Jounieh and continue to the north. After reaching the small village of el-Aqaybe (about 500 meters south of the Nahr Ibrahim village), turn right just before the Byblos Bank building, and follow the road that passes underneath the highway. After about 500 meters, just after the gas station, take a left turn toward Yahchouch and Mradiye, leading you to the right banks of Nahr Ibrahim.
The quickest route coming from Beirut, which avoids the Jounieh traffic, is to take the exit before Jounieh towards Faraya. Continue up for 30 minutes until reaching Mayrouba and take the exit towards Akoura and Lassa, and drive past a strange wasteland of quarries from which you can see the Jabal Moussa Reserve. After 20 minutes this road with joins with the road on the valley south of Nahr Ibrahim.