Park Güell produces more confusion than any other sight in Barcelona, and it all comes from one fact: it is two places with the same name. Most of it is a large free public park. The part on every postcard is a ticketed zone with timed entry and a cap on numbers. Visitors who do not know that arrive expecting to wander into the mosaic terrace and find a barrier. Here is the whole arrangement.
In short: You need a ticket for Park Guell only if you want the monumental zone, the part with the mosaic terrace, the dragon stairway, the hall of columns and the two gatehouses. The large wooded park around it is free and open like any public park. Monumental zone entry is a timed half-hour slot with capped numbers, so book online from the official site, ideally the first slot of the day, because it sells out in season even though it is the cheapest of the Gaudí tickets. The park sits on a hillside, so the walk up from the metro is steep: look for the outdoor escalators on one approach, or take the bus that stops closer to the gate.
The two parks
The free park is the wooded upper area, hilly and genuinely pleasant, with paths and very few people compared with the other part. Since the regulated zone was enlarged, the ticketed area covers about 12 of the park’s hectares, including the Laundry Room Portico, the best known of the leaning stone colonnades, so check the current map on the official site before assuming a feature is free. It is open like any public park.
The monumental zone is the core: the dragon stairway, the Laundry Room Portico, the hall of columns, the two gingerbread gatehouses and the long undulating mosaic bench around the terrace with the view over the city to the sea. This is ticketed, timed and capped.
Almost every photograph you have seen is of the second one.
Both are worth your time, and knowing which is which before you arrive is the difference between a good morning and an argument at a gate.
The ticket
Timed entry, booked online, for a specific half-hour window.
Capped numbers, which is why it sells out despite being inexpensive.
Cheap relative to the other Gaudí sites, which is exactly why people assume it does not need booking.
Residents of the city have separate arrangements, which is not relevant to a visitor but explains some of the confusing signage.
Buy from the official site. Resellers add a margin to a ticket that is already the cheapest of the Gaudí group.
Timing it
The first slot of the day is the one worth having. The mosaic bench nearly empty, cool air, and the light across the city before the haze.
The last slots are the other good option, with warmer light and a thinner crowd.
The middle of the day is hot, exposed and full, since this is an outdoor site with limited shade in the monumental zone.
Allow more time than the slot for the walk up and for the free park afterwards.

What to actually see
The terrace and the bench. The long serpentine seat covered in broken tile, curving around a plaza with the whole city below it. This is the thing.
The hall of columns beneath it, with its tiled ceiling medallions.
The gatehouses, which look like something out of a fairy tale and are the most photographed small buildings in Barcelona.
The dragon on the stairway, which is a lizard, and which has a permanent queue of people waiting to stand beside it.
The Laundry Room Portico, the leaning stone colonnade inside the ticketed area. More viaducts run on up the hillside, and the official map shows which side of the ticket line each one sits on.
The woodland above, where you can walk for an hour and see almost nobody.
The viewpoint at the top, higher than the terrace and skipped by most ticket holders. Check on the official map whether your route to it runs through the ticketed or the free area.
Where it fits among the Gaudí sites
Park Güell is the outdoor Gaudí and it complements the others rather than competing.
The basilica is the overwhelming one and the one to book first; our complete Sagrada Familia guide covers it.
The houses on the main boulevard are the domestic Gaudí, interiors rather than landscapes, and choosing between them is its own decision; our comparison of Casa Batlló and Casa Milà sets them side by side.
All of them together are more than most short trips can hold, and our full Gaudí guide covers which to prioritise for the days you actually have.
The usual sensible pairing for a first visit is the basilica, one house and this park, in that order of priority.

The short version
Park Güell is a large free park with a small ticketed core, and the ticketed core is the part in every photograph. Book a timed slot even though it is cheap, because numbers are capped and it sells out. Take the first slot of the day for an empty mosaic bench. Find the escalators or the closer bus rather than walking up the hill from the metro in the heat. And once you have seen the terrace, walk up the hill, where the view is better and the crowds thin out.
