Q: We are 5 adults with 4 cases, can we fit in one taxi to go to store the luggage for few hours before we check in the cruise, because we arrive early in the morning.
A: You can travel to Barcelona Sants Rail station from the Airport on the RENFE train that runs from the airport. You can easily take on you luggage on the RENFE train. Barcelona Sants (Estacio Sants) have a manned luggage storage department and you can leave your luggage there.
Most Barcelona taxis are licensed to carry a maximum of 4 people and no more. There are a much smaller number of Taxis that are licensed to carry up to 6 passengers however you would either need to reserve these in advance or specifically ask the taxi attendant to find a taxi for 6. The other alternative is to hire 2 Taxis. Most tourists make the mistake of thinking that all van taxis have a license to carry 6 people however this is not the case. Only a small number of van taxis actually have the special license to carry 6 people.
You say you only have a few hours - this does not leave you much time to see much of the city. If you had half a day then perhaps it is worth storing your luggage and having a look around but with only a few hours then you really don't have much time.
For more information on Barcelona taxis, Transport between Barcelona airport and the city centre etc see our Related Articles below.