The name Costa Brava has been attached to package holidays for sixty years, which does the coast a disservice. Brava means rugged, and that is literal: this is a shoreline of pine covered rock headlands with small coves cut into them, clear cold water, cliff paths that connect beaches with no road, and a handful of towns that were fishing villages until the 1960s. There are resort strips on it as well. The point of a day trip is knowing which part you are going to.
What the coast is actually like
Coves rather than beaches, mostly small, some coarse sand and some pebble, separated by rocky headlands.
Clear water, colder than the city beaches and far cleaner.
Pines to the waterline, which is the visual signature of this coast.
Old towns on headlands, several with walls and castles, at the southern end.
Fishing ports and Dalí country further north, near the French border.
Resort development concentrated in a few specific places, which are easy to avoid if you know their names.
Getting there
Bus from the northern bus station in Barcelona runs direct to the main coastal towns and takes between one and two hours depending on how far up you go.
Train goes inland rather than along the coast for most of the way, so it usually means a train plus a local bus or taxi.
Car is the flexible option and the only practical way to string coves together, with the summer parking caveat.
Boat services run between some coastal towns in summer and are a pleasant way to move a short distance.
One town per day trip is the realistic ceiling without a car.
Where to go for what
A medieval town with a swimming beach below it at the southern end, which is the easiest full day from Barcelona and gives you a castle, a cove and a path in one stop.
The middle section, for coves, the coastal path and small hotels rather than sights.
The northern fishing ports, for harbours, seafood and the Dalí connection, which need an overnight from Barcelona.
Inland, half an hour back from the coast, for medieval villages that most beach visitors never see.
The Dalí triangle, linking his museum inland, his house on the coast and his castle, which is a trip in its own right.

Practical notes
The water is colder than the Barcelona city beaches, noticeably so before June.
Sea urchins are common on rocky entries. Water shoes solve it.
Coves have no facilities in many cases, including no shade, no water and no toilets. Take what you need.
Restaurants close out of season in the smaller places, sometimes from November to Easter.
Parking at the popular coves fills before ten on summer mornings, and several charge.
Summer traffic on the coast road is slow, and a thirty kilometre drive can take well over an hour in August.
Where this fits in a Barcelona trip
The Costa Brava is a full day, and it is the best answer to a hot week in the city.
For the other classic day trip from Barcelona, inland and upward rather than out to sea, our guide to Montserrat covers the mountain and the monastery.
For the nearer, easier beach town on the coast south of the city, reachable in under an hour, our guide to Sitges covers the alternative.
And for the inland city that pairs naturally with a northern Costa Brava trip, our guide to Girona and its old Jewish quarter covers what to see there.

The short version
Pick one town rather than a stretch of coast if you are going by bus, and hire a car if you want three coves in a day and it is not August. Walk a section of the Camí de Ronda, which is the best thing here and costs nothing. Take water shoes for the rocky entries and water for the coves, which mostly have no facilities at all. Go in late spring or September rather than midsummer, and check that anywhere you are relying on for lunch is actually open if you come out of season.
