Not sure what they call the area in Lisbon where the ship docks but it is virtually right underneath the big suspension bribge in Lisbon , again P&O will supply a free shuttle bus to the city centre which is about a 10 minute bus ride. Personally i was not very impressed with Lisbon so again unless you want to see something specific then just do it yourself and save that all important beer money, can`t really remember many people going on the P&O trips in Lisbon compared to some of the other ports so that might be telling you something !, i would suggest a good night out instead , enjoy the cruise.