Arrival Port
The arrival port is where the cruise ends, and whether it matches the departure port changes how the whole trip gets planned.
Round trip
Arrival port is the same as departure — the easiest to plan, since one flight or drive covers both ends of the trip.
One-way
The cruise ends somewhere else entirely. These often visit more distant regions, or reposition a ship between seasons (see Cruising Area) — but you'll need travel arrangements from a different city than the one you started in.