In Lisbon and Porto, currently these activities below are very popular and worth doing, from Monuments to fun attractions to see in the city, tours, etc.
Lisbon hop on hop off bus + boat option (very helpful to move on the city), S.Jorge Castle, National Tile Museum, Tagus River Cruise, Belém Tower and Monastery.
A Fado Music show (only show or with dinner or drinks), Lisbon food wine tour, full day tour to Sintra (Pena Palace), Cascais and Cabo da Roca, etc.
The Banksy Lisbon Museum, Lisbon Oceanarium, Amphibious bus trip, tuk tuk tour in Lisbon,
(Do not forget that it is important to book some in advance due to the movement of people in these coming months, Portugal is becoming a very popular tourist destination).
In Porto you have the option for the hop on hop off with cruise included also, 2 days, with Porto wine tasting included, very good and helpful to move on the city and along the Douro River.
For the Douro Valley, I have done day trips and loved it! With transfer from Porto, Boat trip, amazing views, we visited a winery. Very very good.
(Links below)
For Rental Car we recommend “Discover Cars”, with full coverage and much more cheap, highly recommended. (Link down below).
More info about the main activities
Lisbon
Sintra tour from Lisbon (Pena Palace/ Cascais/Cabo da Roca) day trip:
Tagus River cruise:
Lisbon food wine tour:
Lisbon hop on hop off:
Tram 28 Hills Lisbon hop on hop off 24h:
Belém Tower:
Belém Jerónimos Monastery:
Tuk-Tuk tour, with hotel pick up, (reasonable price):
S.Jorge Castle skip the lines ticket / tour:
Lisbon National Tile Museum:
Lisbon evening Fado + porto wine (20€):
Fado show + dinner + walking tour Alfama (49€):
“Fado in Chiado” show (50 min) / (20€)
Banksy Lisbon Museum:
Oceanarium Lisbon:
Amphibian trip:
Porto / Douro Valley tour from Porto:
Porto hop on hop off bus with cruise and wine cellar / wine tasting:
Rental Car, “Discover Cars”: