Portugal in 10 days

Not possible to open jaw into Lisbon out of Porto? (or vice versa) to save yourself the return trip to Lisbon?

Flying open jaw as suggested would make sense with this itinerary. 5 hotel changes in 8-9 nights (eq 7-8 days) iis exhausting & wastes precious sightseeing time. If you aren’t seeing anything on the way to Porto, take the fast train to Porto, under 3 hrs, and rent a car from there to go to Douro. I think you’re short changing Lisbon. Sintra is an easy day trip from Lisbon & would eliminate 1 hotel change.

Agree with Marika! I think you need more days in Lisbon. So many things to see and do and yes you should include a whole day in Sintra (45 min away by train each way), it's a lovely and quaint and very different from the city. You have Quinta Regaleira, The castle and the Palace to visit as well as just meandering in the streets and having a nice lunch. I would also suggest spending a day or at least a whole afternoon in Obidos (between Lisbon and Porto)

I agree with those who suggest giving Lisbon one more night. There are so many attractions there and the city itself to explore. We took the train to Porto, spent three night and then travelled by train to Pinhao for two nights which we felt was plenty. The train station is a gem with it’s tiled walls.. It is a very tiny village with few hotels and restaurants. The big draw is the beautiful scenery and touring vineyards for wine and port tastings. There are also shorter day cruises on replicas of the boats used to transport barrels of Port to Porto. Sintra is well worth your time with the forts and castles to tour. You would save time, travel and possibly spend less if you returned home from Porto. Have a great trip.