Portimao in the Algarve to Lisbon

For a one way ticket you just leave the return date blank.

It does not allow me to "submit" .... ?

If your travel dates are over 60 days it won't work, wait until you're within the 60 day window otherwise it should work.

My travel dates are less than 30 days...still will not let me "submit".
Going to try Omio....hopin' they're more user friendly....

Well it's certainly working for me. In Portugese Lisbon is Lisboa- you then need to select from the drop down menu which of the 6 stations you want. Oriente is the main interchange station, Santa Apolonia is the much older and more central station. You usually have to change at Oriente to reach Santa Apolonia.

IMO those are the only 2 of the 6 to choose between that.

But you have to choose which station from the drop down menu.

When you do that CP is a pretty user friendly website. Book anywhere else and you are dealing with a third party and paying an inflated price for doing so.

Rede Expressos (the de facto national inter city bus operator) also run a number of bus/coach services a day both to Oriente and to Sete Rios bus stations in Lisbon- both are on the city subway lines- https://rede-expressos.pt/en/timetables

Again you want Lisboa rather than Lisbon.

Thank you so much for your thorough information!
I will try that....yes, I see the dropdown menu.
Again, much appreciated!
Since you know all of this, let me know if you have any favorite eateries! :-)
Obrigada!