I should be at the Cruise Terminal at around 9 am, and will have no luggage with me. Google Maps says around 12 minutes by car to Ribeira. But an hour or over by public transport. Any further details on the local transport that might suggest faster times by public transport?
When you hop off the Cruise Terminal, you can walk by the beach for a few minutes until Rotunda da Anémona and then take bus 500 to Praça do Infante, in Ribeira. On your way back to Leixões, you may want to take the classic tram from Praça do Infante till Passeio Alegre, which is slow, but surely quaint — especially on a sunny afternoon.
Photo allegedly courtesy of Rui Jorge Pires
I would not recommend that you take the metro from Leixões till Ribeira. Firstly, it is infamously slow, as it is actually a (surface) tram until it reaches central Porto. Also, it is slow while traveling in uninteresting parts of Matosinhos and Porto — unlike the classic tram, which is surely slow but slow while traveling by the beautiful riverside. Secondly, the metro does not stop in Ribeira. It stops in Trindade. Then, you either take the metro to São Bento or Jardim do Morro and then walk downhill, or you walk downhill from Trindade itself.
This page has lots of details about the port and transportation options, including pictures and detailed itineraries.
Arriving at the Cruise Terminal, it goes like this:
- You take the shuttle bus from the terminal to the exit of the port
- At the exit, you have several options, including:
Taking a taxi there
Note that when looking at Google Maps Street View, I don't see a taxi on any of the pictures over the years. They probably come when a cruise ship arrives. The usual issue in that case (don't know if that applies here or not) is that there may not be many taxis, so if you're not among the first there you may have to wait a while for a taxi. You could also book one in advance, or call for one, or call for an Uber or other equivalent service.
Taking the "metro" (light rail, really), which is a few minutes away but is quite slow
Taking the bus (250m, 3 minutes), which seems to be the fastest option in your case. Line 500 gets you to the city centre in less than 30 minutes, you'll have a few options about where you get off depending on where exactly you want to go.
The page linked above also says you may find an hop-on hop-off bus at the port exit. Those can be a good way to get around the city but they are generally a bit slow, infrequent and more expensive than regular public transport, so it depends on if you want to go quickly to some place or if you want the bus to show you around.