The frequency of the Barcelona Bus Turístic and the City Tour Barcelona—the two main operators—varies significantly depending on the season, but generally, you can expect a bus to arrive every 5 to 15 minutes. During the peak summer months (June through September), buses run at their highest frequency to accommodate the massive influx of tourists, often appearing every few minutes at major stops like Plaça de Catalunya or the Sagrada Família. In the winter low season, the intervals may stretch toward 20 or 25 minutes, particularly on the less popular routes. It is important to note that Barcelona’s buses operate on two or three distinct routes (Blue, Red, and Green), and the frequency can differ between them. The Blue and Red routes are the most frequent, while the seasonal Green route along the coast may have longer gaps. Traffic in the Gothic Quarter or around major events can also cause delays, so it is always wise to use the operator's real-time tracking app to see exactly when the next bus is approaching your specific stop.