On a maximum of 2 travel day you can also travel in your country of residence. On a travel day (00.00-23.59 CET) you can board as many trains as you like. 

When are you looking to travel ? Please note that the Eurostar has a quota for passholders (30€ seat reservation) and it can sell out days or weeks in advance.

Check availability here : https://www.b-europe.com/EN/Booking/Pass#TravelWish

If London - Paris is full, check London - Lille. Generally evening trains have more availability.

If you have questions mention travel date and we'll gladly help.

The TGV Paris - Barcelona costs 35€ but the price can be reduced by taking a slower regional train across the border.

There are also night trains from Paris to the Spanish border.