I emailed
DCL and the Magic should be docking at Santa Apolonia in Lisbon.
According to what I found on Trip advisor it should be easy to get to the main centre of Lisbon.
THis is a cut and paste I think the fares are old.
If your ship does dock at Santa Apolonia, then you walk over to the big train station by the military museum, and go downstairs to the metro (blue line). Buy a ticket from the machine (E1.25 = E0.50 + E0.75) and ride over a couple of stops to Baixa-Chiado and get off. You have a choice to climb up to Chiado or climb down to Baixa (using either stairs or escalator). Return by putting the ticket in the machine and adding E0.75 for the return trip. If you think you will ride a lot of transit, then purchase the day card for E4.00 at the kiosk in the station, and ride all of the bus/metro/tram/elevador for the entire day.