Almost Certainly by Long distance Bus!
There are no low-cost flights nor train between the two centres.
At present, there are two operators which offer this service:
1) alsa.es
Website url: http://www.alsa.es
One daily service with an extra on 4 days a week.
SEVILLE(Plaza das Armas) 15:00 LISBON Sete Rios 21:15 - Thurs/Fri/Sat/Sun
SEVILLE(Plaza das Armas) 23:59 LISBON Sete Rios 07:30 - Daily
Price - Single - One Way - € 35.00
2) Damas/EVA
website: http://www.eva-bus.com
It is possible to take the morning Seville bus to Faro and connect with a forward service to Lisbon as follows:
SEVILLE(Plaza das Armas) 07:30 FARO 10:10 - Daily
Price - Single - One Way - € 16.00
FARO € 11:00 LISBON Sete Rios 14:15 - Daily
Price - Single - One Way - € 19.00
Total Price Seville - Lisbon € 37.00
Apart from this getting a lift with some one is the only other way
