On 12 August 2026 in Barcelona (Cataluña) the eclipse will be partial: the Moon covers up to 99.8% of the Sun's disc around 20:29:08 (Spanish peninsular time). There will be a noticeable dimming, but not total darkness.
Because it happens right before sunset, the Sun will be very low (3.9°). That's why what matters is not just being in the right place, but having the west-northwest horizon clear of hills and buildings.
Data computed for the coordinates of Barcelona (41.3874, 2.1686). Verify with the IGN (Spain) before travelling.