News regarding public transportation in Barcelona
From January 1st, the famous T-10 travelcard changes its name to T-CASUAL and increases its price from 10.20€ to 11.35€. But the most important change is that it CEASES to be multiperson and becomes UNIPERSONAL. Therefore, those that have visited in the past and shared a T-10 travel card with your travel party, DO REMEMBER this is no longer possible and that each person riding the public transportation needs to have his ticket, be a single ticket, be a travelcard but for his/her own use only.
This questions the convenience of the T-CASUAL for, wait for it, "casual visitors" to the city because, as you know and have read many times in the forum, those on short visits to Barcelona don't really use public transportation that often. Thus, plan your itineraries carefully and evaluate whether you will need to take public transportation that many times.
Your options for a short visit (a few days) will be:
T-Dia Card (10,50€) allows an individual trip allowing an unlimited number of journeys to be made in one day, and in zone 1, on all operators in the integrated transport system, including metro travel (L9) to/from the airport.
T-Casual Card (11,35€) allows an individual trip allowing 10 journeys to be made in zone 1, on most operators in the integrated transport system. It expires at the end of February the following year after the purchase. Note that T-Casual cards for more zones do exist, check the website. This card somehow 'replaces' the existing T-10 travel card.
HOLA Barcelona Travel Card which, for around 15€ offers individual unlimited travel for 48h on (most) public transportation means in zone 1. Also available for 3days, 4days and 5days. It allows metro travel (L9) to/from the airport.
Single ticket (2.40€)
Also, the 'new' T-Grup Card ( 79.45€) if you travel with a party. It will remain the only multiperson card and it'll offer 70 journeys to be used with 30 days for zone 1. This card somehow 'replaces' the existing T-70/30 card.
Again, neither the single ticket nor the T-Casual is valid for the metro journey (line L9) from the airport to the city and vice versa. For that, you need a special ticket to ride to/from the airport that will cost 5.15€ (from January 1st). However, you will continue to be able to use the new T-Casual as you did the T-10 to ride the train (Rodalies) to/from the airport to the city centre (Sants, Passeig de Gràcia or Estació de França) as well as the #46 bus (airport-Plaça Espanya).
For the Aerobus, you will continue not being able to use a T-Casual as it's run by a private operator.
Confused? well, we locals we are as well :)