One way means that the route sets sail from one marina and ends in another marina, rather than returning back to the same place.
Our Croatia, Dubrovnik Route is a one-way route and the starting/ending marina depends on the week you book. See details below:
Week 26 - Sets sail from Dubrovnik and sails north ending in Trogir (near Split)
Week 27 - Sets sail from Trogir (near Split) and sails south ending in Dubrovnik