Portugal looks small on a map of Europe, which is how people try to do Lisbon, Porto and the Algarve in one short week. Lisbon is hills, a river estuary, and trams that are public transport as well as a photograph. Porto is granite, another river, and a different kitchen. The Algarve is the south coast, built around beaches and golf, and not a suburb of either city. Portuguese is the language. Spanish will not reliably carry you in a market in Évora, even though the countries share a peninsula.
Comboios de Portugal runs the north–south spine. The Alfa Pendular between Lisbon and Porto takes roughly two hours fifty minutes to a little over three, depending on the service, into Porto Campanhã. Intercidades is slower and often cheaper. The Algarve is a longer rail day, or a flight, or a drive. English is common in Lisbon, Porto and the resort south, and thinner inland in the Alentejo.
Hills in Lisbon are real; the walk from the river up to Graça is exercise. Cards work in cities. Some trams and small cafés still like coins. August is the Algarve and a Lisbon that has partly gone to the beach. Winter is wetter and quieter. One city, or Lisbon and Porto by train, is a complete visit. Adding a beach at the end only works if the week is long enough that nobody is running.
