Barcelona in late August

For the top five attractions in Barcelona—Sagrada Familia, Casa Mila, Casa Battlo, Park Guell etc— it’s best to buy your tickets online in advance by reserving the time in the morning the attraction first opens.
There are at least a couple reasons for doing this:: Barcelona is the top cruise ship destination in all of Europe. Cruise ship tour groups usually begin to mob the most popular attractions sometime around 10 am and begin to recede around 3pm; when the attraction has no visitors the moment the doors first open, the first hundred people ( or 200, or more) are admitted. As the attraction fills up with the most people allowed at a time according to fire safety regulations, the pace of admissions slows and the lines outside the attraction will begin to lengthen. And continue to lengthen. If you read about the crowds at Sagrada Familia waiting to get inside, you’ll learn the lines outdoors can be daunting. And if you have a timed ticket for entry at 10:30 am there is no guarantee that they can safely admit you right at 10:30 am. At 9:30, that is not a problem.
The other reason to reserve the opening time is that the average high temperature in Barcelona during August is a humid 85 degrees. So, standing around in outdoor lines in the summer heat is best avoided. I’ve been to Dubrovnik in 2021 and Istanbul in 2022 when there were no cruise ships in port.
Both cities were wonderful.

the opening hour at Sagrada

Kenko,

That’s a very helpful response! So, is planning to visit Parc Guell in the late afternoon a bad idea? I was thinking it would thin out and we can be up there for sunset time.And is there any benefit to buying the combined ticket with Sagrada Familia on the Barcelona Card website? It seemed crazy expensive, 187€ for he 4 of us even with one free kid ticket. For the 2 Gaudi houses, if you had to choose one, which would it be? Asking because we actually only have 3 mornings to visit top sites, so we have to choose one; and also likely our kids would only have patience for one. If it’s Casa Mila, Is it worth also going back for the evening experience? I saw there is a combined ticket option.

Thanks,
Vlad

Park Guell closes at 7:30 pm. That is one attraction I think you could visit closer to closing time on a weekday (Sundays could be different).
The Monument Zone in Park Guell reportedly only ropes off the Monument Zone at 9am when tickets are required for entry. There’s no fence and some online reports are that you can enter the Monument Zone for free if you go between 7:30 am and 9am and again after 7:30 pm. The rest of Park Guell is free to everyone.
I can’t comment on the transit cards available as I’ve not dove into the details but staying in Eixample means you’ll be close to the underground Metro/Train station “Passeig de Gracie.” That metro station gives you direct links to the “Sagrada Familia”
Metro station and the “Lesseps” metro station, which is a 20-minute walk from Park Guell’s main entrance.
At $30 per adult entry ticket, I decided to see Sagrada Familia and Casa Batllo rather than Casa Mila.
Barcelona does need a visitor card like the Copenhagen City Card that covers most attractions. As far as I know, there are no Barcelona Cards that cover the full admission cost to the Sagrada Familia, Casa Battlo or Casa Mila. The Picasso Museum is free on Thursday evenings.

With our family of four we chose to purchase 10 pack transit tickets and avoid the "cards".
Parc Guell has become a shadow of it's best days. It is costly to enter, fenced in an people tend to hang around longer standing in the most photogenic spots in an attempt to "get their moneys worth" form the entry fee. I advise skipping this now over rated and over crowded location.
Actually Sagrada is also an excellent late afternoon experience for the light pours in from the setting sun providing wonderful lighting. During the past 30 years we have been on multiple occasions during different times and enjoyed the experience. The streets directly adjacent to Sagrada are now infested with terrible quick service restaurants and tourist shops so advise avoidance.
Casa Mila is our favorite and do advise early morning visit.
Arriving via plane or train Monday? Makes a difference on available time, however you should still have ample daylight to utilize.
Stay off La Ramblas, unfortunately it is junk tourist filled and big pick pocket target.
Strongly encourage a visit to the academy of music the Palau. An air-conditioned experienced!
https://www.palaumusica.cat/en
Monsterrat, a full day experience our family enjoyed
https://www.barcelona.de/en/barcelona-excursions-monastery-montserrat.html
Montjuic, enjoyed the cable car experience and combined with a visit to the waterfront. Family evaluated it as one the experience we could have passed on and been content.

Steven, thanks for a very helpful response! We're arriving via train at about 2 pm. I think for that afternoon we will just settle in, do a bit of food shopping, and walk around. For Sagrada Familia, do you and others recommend paying the additional fee to go up one of the towers in an elevator? I'm not sure this will be of interest to our kids or worth the additional expense. Also, does Sagrada Familia get lets crowded by say 4 pm or so? I'm concerned about showing up the same time as a whole mass of people arriving to see the light through the stained glass. Thanks as always!

La Sagrada Familia sells timed tickets. The first time slot to sell out is usually the first one as people try to beat the crowds. In 2019 I walked past LSF around 4 PM and there was a significant crowd there either waiting for their entry time or lined up to buy tickets. I'm not sure the timing affects crowds much. It's just that if you have the first time slot, you and the others with that entry time walk into an empty church rather than a church already pretty full of people left over from earlier entry times. Even with the first time slot, there will be influxes of people as the clock moves along.

I visited Parc Guell at 5:30 pm on a Sunday, and there was no line to get in. Also, although they stop admitting ticketholders at 7:30, you can stay past that time if you are already in the park. Also, it seemed to be the case that you can enter before your ticketed time if you arrive early - my time slot was for 6 pm, but I entered about 40 minutes early, as the guard said it doesn't matter.

Depending on distance to your abode please consider doing your grocery shopping in the basement of El Corte Ingles at Catalunya Plaza. I suspect your family will enjoy this experience.

We had a great time taking none of the towers with our families, try and obtain a photo with family standing in a line, best done if a fellow traveler will shoot back up at your family. The steps are super narrow so take your time with traversing the tower. We have done both towers and offer no preference.

I, too, preferred Casa Mila to Casa Batllo, though I definitely enjoyed both. I thought Casa Mila was more attractive. It also was a bit less sardine-like (this was in 2016)--though if you go only to Casa Mila, you will not think that possible. I was told back in 2016 that Casa Batllo was admitting more people per day.

I haven't done a night visit but wouldn't consider that necessary. The privately-run Gaudi sites keep adding extra-cost features; frankly, they smell like cash-grabs to me.

I'm finally getting around to making bookings for Sagrada Familia, Casa Mila, and Casa Batllo. For Sagrada Familia, is visiting one of the towers essential / recommended, and does it matter which one to choose? Also is it worth the hassle to try to acquire a Carnet Jove for our 15 year old to take advantage of that half price offer? I'm not clear if she's even eligible as a foreign visitor. For Casa Mila, is the Full Experience adding the mezzanine visit with the virtual reality glasses worth the extra 10 euros? And any tips for booking Casa Batllo or all 3 together? Planning to book all 3 at opening times on success days as follows: Day 1 - Casa Mila. Day 2- Sagrada Familia. Day 3 - Casa Batllo. Thank you!