The big picture in Spain is of a continuous upwards trend in property prices, though the market seems to have taken its foot off the throttle with more gentle price rises seen in 2019 than was the case earlier.
But the big picture can be deceptive. Spain is a very patchy market, with huge regional variations. That's particularly the case when you look at where foreign purchasers are putting their money. Huge areas of Spain are almost untouched by foreign interest (the north, west, and middle sized cities) while foreign buyers are concentrated along the coast, in Barcelona, Comunidad Valenciana, Andalucia, and the Balearic islands. Add Madrid to that mix and you have three-quarters of all sales to foreign tourists.
Even within these areas, property transactions are heavily concentrated; a third of sales in Andalucia are in just one of its eight provinces, Malaga, and a third of sales in Malaga are in just two cities, Malaga and Marbella. New building developments are equally concentrated.
Foreign purchasers account for 20% of the market - significantly more on the coast. That's fine when you're in an area where Scandinavian, Dutch, German and French buyers are in the majority, but some areas are far more orientated towards British buyers. Estepona, for instance, is more Scandinavian - Torremolinos is more British. No one knows quite what the impact of Brexit will be, but to avoid uncertainty, avoid anywhere that has more than two cafes selling full English breakfasts! (Let's be serious: ask the local agents who the main buyers are.)
The end of city centre AirBNB?
Many Spanish cities have seen the whole centre taken over by bars, restaurants, and AirBNB. There's nowhere for locals to live, or to buy their groceries.
That made good money for investors, with yields on AirBNB in some areas well above 10%. But an increasing number of cities have brought in regulations that make short term letting considerably more difficult - and in the case of Madrid, practically impossible. (In the hyper-centre, if you don't have a separate entrance to the building for tourists, you can't let your property short term. This would make 95% of existing lets illegal.) In Barcelona, tourist lets have been entirely banned in the Gothic Quarter.
Soб if you want to invest in short term rentals, you should be looking for villas, not city centre flats. We'll get on to the subject of exactly where to look a little further on.