From the airport:

1. Taxi. Taxis in Valencia are very cheap and safe. If there are more than 3 of you, you will need to request a taxi for at least 5 people, as taxis normally only carry 4. When you arrive at the port, the taxi driver will collect the entry ticket and take you 300 metres to the check-in point.

2. The best alternative is the underground, which is inside the airport and takes you to Maritim Serreria, 1 km from the port.

From the train station:

1. Taxi

2. Underground from Xativa to Maritim Serreria.

By car: you can drive directly to the Marina Sur port. There is a barrier at the roundabout. Take a parking ticket and drive another 50 metres to the check-in point and the parking.