Me and my partner will be on a 2 weeks trip to Portugal and North Spain. We wanted to rent one car which we can pick in Lisbon and return in Barcelona, but I can't seem to find a company which allows that in a reasonable price. Can you assist?
Also, in case we will have no choice but renting two separate cars for the different countries - to where would you advice arriving crossing the border from Porto? Are there other options than Vigo?
Try Auto Europe : http://www.autoeurope.eu
A German intermediary offering excellent pricing across Europe. I live here in Spain but have use this service before for car rentals here in Spain. In fact, I just rented with them in Ibiza last week and it was the best rate saving a couple of hundred Euros versus the other companies. Not sure the cost on delivery car back to different location/country but give them a go.
It's very expensive to deliver a car in a different location, and I don't know any company accepting it the two countries. Is it important to go to Barcelona? If not, you may plan a circuit starting and ending in Porto, exiting to Vigo, visiting the north of Spain towards San Sebastian de los Reyes, and returning by Burgos and Salamanca, re-entering Portugal in Braganca or Vilar Formoso, to follow Douro valley back to Porto.
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My car rental site of choice is www.novacarhire.com, which is an Irish-based company that reliably gives me a very competitive price and uses reputable car hire companies (etc. Hertz, Avis, Budget).
Out of interest, I tried a couple of random dates and compared the collect Lisbon/drop off Barcelona option with the collect and drop off at the same airport (both Lisbon and Barcelona). The penalties for collecting and dropping off at different airports are painfully steep, which I also suspect has to do with the fact that you are not just dropping off the car at a different airport, but also in a different country.
Given the recent tightening of control over car hire in Spain after the tragic Barcelona attack this week, I really think you might reconsider this plan.
You mention in your post that your trip is to Portugal and Northern Spain. So it's a little difficult to understand how Barcelona (in the extreme east Spain) features in this plan?
Perhaps you can provide us with a little more insight into what you'd like to do/see to better inform our responses?