Can I buy weed on the streets in Barcelona?

The laws on cannabis possession and use in Barcelona are relatively simple. Smoking and possession of marijuana is completely legal within the confines of your own home or within a cannabis club. As long as you aren’t smoking or in possession of cannabis in a public place, you are not breaking the law. Even as a foreign national you are within the law. So don’t do anything illegal.

Illegal activities under the current law would be do buy cannabis from a street dealer.