First of all I want to say, they were all very interesting though different ports of call, with a lot of history and sights to see. I think it always best to have some common link in cities or regions I travel to, and here it is clearly "Al Andaluz, ie the Moorish occupation of Iberia, and also the very beginning of European expansion and the voyages of discovery, some two poignant topics these days, so very interesting to experience them in life.

First, Malagà, at the costa del sol, where we embarked.
We arrived a day earlier and booked in a very nice, colourful, stylish hotel in an old andalusian house with a patio, in the old center, near the Teatro Cervantes and Picasso's birth place.

There is a public bus between the Plaza Marina in the heart of the city center and the cruise terminal, 2 EUR per person per ride (5 mins, as much as for the 40mins airport bus...). walking to the cruise terminal is really no option as there are heavy roadworks on the mole. The Empress is docked ont he outer end of the Mole.
You can see the principal sights of Malagà in a big walk, on half a day : from Plaza Marina in the pedestrian high fashion Calle Larios, the Plaza Constitucion, the Cathedral, entrance at the side (5 EUR, with an audiophone), the Picasso Museum in an old stylish aristocratic palace (7 EUR), throught the maze of old moorish streets to the Plaza de la Merced, in renovation, with a nice obelisk, with the small but very sympathetic museum in the Casa Natal de Picasso (Picasso's brithplace - 1 EUR) there is a nice little tavern, Libros, at the other corner, from the there it is a very short walk to the entrance of the old Moorish Castle, the Alcazaba, near the Roman Theatre, on the rock above Malaga. You walk up the hill through the fortifications, and near the inner courtyards there is a lift down to sealevel, to a street beneath the Ayuntamiento. From there you walk through the pleasant park, with a "gloriette" with art deco tiles back to the Plaza Marina for the Bus.

Portimao is the major port of the Algarve in Portugal, and the second city after Faro in Algarve.
The ship docks at the new Cruise terminal between Portimao and Praia da Rocha. We had made an agreement with a rental car agency to bring a rental car to the cruise terminal, which was there and which was fantastic.
With the car we went to the Cabo Sao vicente, an hour drive, the extremity of Europe, the cape sits between the Atlantic, this side was completely covered in fog, and the Med, this side had blue sea and a blue sky. The lighthouse was blasting a fog horn. The litte museum has a statue of Prince Herny the Navigator, who had made Algarve his base for the first european voyages of discovery, which adorned the portuguese liner "Infante Dom Enrique". From there we went to the opposite Cape, where the Sagres Fortalezza is, allegedly the place of Heny's navigation school, but probably where he lived. You can walk around the cape there. On the road between Sagres and Lagos is a very old chapel, the oldes church in the Algarve, built by the Templars, the Nossa Senhora da Guadelupe, with a very good, small, interesting museum about, who else, Henry the Navigator...
Lagos is a small historical town, with an interesting centre (and the first slave market....) very small to walk around.

I liked the Algarve from what I saw. It has an imposing coast line and is much much less spoiled than the spanish Costa del Sol, which is quite shabby and chaotic.

In Lisbon the time was limited, so all was very tightly organised. Empress docks at the Santa Apolonia cruise terminal, at the foot of the Alfama hill, the old center, with the moorish castle on top, next to the Santa Apolonia Train Station, and the terminal of the Blue Metro line (la gaviota, or seagull line), so access to the city is very easy.
In Lisbon we had prepared a nice walk from the Chiado Metro Station to the Santa Justa Elevador, an iron belle epoque contraption by a disciple of Eiffel to tackle the height difference between the high district of Chiado and the low Baixa area, destroyed in the 1755 earthquake and rebuilt by marquess Pombal, so the Pombaline city. Near the elevator in Chiado is the Carmel church (convento do Carmp) which is in a ruinous state since this earthquake. After the Rossio square we took the iconic historic tram, nr 12 to the alfama, Castel s.Jorge, which we visited, and from where we walked down the hill to the cathedral (Se) andthe Parço do Comercio where we took tram 15 to Belem, where we remarked that we were robbed. Instead of visiting the UNESCO world heritage wonders of Belem we spent the remaining time of our Lisbon visit in the Tourism Police Station on Restauradores Square near the Rossio train station...

Nevertheless I liked Lisbon, it is charming, nice colours, the antique trams driving all over the place give it a pictoresque feel, it is walkable (except for the distance to Belem), there is a lot of history, there are beautiful viewing points all over the place, the Bridge over the River Tagus is majestic...
I thought it a stylish place, though a little bit rough these days and not really gentrified (luckiliy).

Our last stop was Tanger, which is something special. It is not really a place geared for tourism in the modern sense, though it has received Western visitors for a long time. It is certainly not gentrified, but also not grim or so. It is an Arab town, so you have to expect, certainly in the port and the streets leading up to the old town, that you are accosted, also by children : "guide, guid", "medina" "souk". Loaded with a good map, I don't think you need a guide, but the Medina is certainly a labyrinthic maze with small dark alleyways, full of unexpected corners etc. The names of the streets are clearly marked though.

You can easily walk from where the ship docks to the Grand Socco, the factual centre of the city (the corniche at the beach is alittle further) Place du 9 Avril 1947 is its official name. It is bit uphill. there you go through a gate to the Medina, and up the Rue d'Italie and the Rue du Casbak further steepily uphill to the Kasbah, the old palace of the sultan. Very interesting, though no Alhambra ofcourse. There is a little stairway from the inner courtyard up to an unexpected garden, full of tangerines.
Also visitable in the Medina is the American Legation Museum (closed on sundays..) and the Fondation Lorin in an old synagogue, full of pictures of Tanger in the time of the Statu.

For other souvenirs of the Statut you can visit the Hotel El Minzah and the Grand Café de Paris on the Place de France.

Absolutely recommended is a visit to the beautiful Anglican church or St-Andrews above the Grand socco in a beautiful moroccon style.

It is a 20 mins walk back to the ship.

Hope this interests you.