La Predera Barcelona - need to ticket ahead for late March ?

I've only visited Barcelona in August, but I'm afraid the answer is that you always need to advance-purchase your ticket for that site. However, if you travel with a smartphone you might be able to book sometime during the day, after you see how your day is going. Alternatively, if you're near Placa Catalunya, you could stop at the (underground) tourist office and get a ticket there for an extra 1 euro. The T.O. itself can have quite a line, though, so I think the web-purchase idea is probably better, assuming there's an option that doesn't require you to print out a ticket. (I have not checked on that.)

Wise advice Ann, I however would like to point out that availability is related to the maximum capacity of each site -which is regulated by Law, under the Health and Safety Regulations- therefore, purchasing at the T.O. does not guarantee availability if the site is already sold out, so to speak.

For info: all the most popular sites in Barcelona tend to be busy all year round. This does not necessarily mean you cannot just walk to the booth and purchase a ticket right away in some rare occasions, but it's by no means the norm. Needless to say that in Easter, Summer, and Christmas you need to pre-book several days in advance.

Oh, absolutely. I didn't mean to imply that the T.O. would have tickets when the site did not. It's just that for the typical tourist wandering around the city, the Pl. Catalunya T.O. may be fairly convenient to stop by. The tickets I bought at the T.O. were computerized; I assume they are hooked into the same system the website uses.

I think it was 2009 when I visited in mid August in the late afternoon, no reservation, minimal wait. I wonder if anyone on here has experience from March 2016.

If I go there, it will definitely be late afternoon or after.

We had an experience similar to David's - When we first arrived at La Pedrera , there was quite a queue . It was early afternoon , and we needed a coffee . Forty minutes later , after our refreshment stop , the line had disappeared and we walked right in ! Hit or miss I guess . If you do go , spend adequate time in the attic where you will see architectural models and plans and will be able to appreciate how Gaudi designed and executed this incredible structure .

I spent at least an hour on the roof top, and I'm not even a Star Wars fan.