Travel from Sevilla to Lisbon

You're probably going to want to fly.

It may seem like an odd choice at first - it's not that far, and everyone assumes that Europe is covered with wonderful, convenient, efficient trains.

Not that corner of Europe. Getting between much of Spain and most of Portugal is usually more challenging than most folks expect. To go by rail requires a bit of a detour and the train takes a while (like 11 hours!).

For this route, flying probably makes the most sense.

The Portuguese are not terribly fond of Spain and transport between them is not easy in spite the close distance. In Portugal we were warned not to speak Spanish, rather speak English if we did not know Portuguese.

A lot of the "conflict" and lack of connections go back to the Franco regime. Spain was somewhat isolated by it's European neighbors so the rail connects are just not there. And even the rail system in Spain is not as developed as the rest of European but Spain does have a terrific bus system. So don't overlook the possibility of buses.

You can fly from Sevilla to Lisbon via TAP Airlines. We have used TAP many times, and have no complaints. Their prices are always reasonable, and they have always been on time.

If you haven't made your airline reservations from Madrid to the US, why not fly home from Lisbon to the US? If you have made your airline reservations, then fly from Lisbon to Madrid. Much easier than ground transportation.