Information consumption is not an independent activity anymore. Instead, it forms part of a continuous connection to the digital space. Thus, users do no often deliberately search for news on social networks. Instead, it is found accidentally amongst other social or entertainment contents. The phenomenon of incidental exposure is an emerging trend in digital consumption, having ramifications for political participation and citizens' understanding of public affairs. This work provides a comparative analysis of digital users' incidental exposure to news in four Spanish-speaking countries, on three platforms: Facebook, YouTube, and Twitter. Samples from Argentina (n = 2,003), Chile (n = 2,005), Spain (n = 2,006) and Mexico (n = 2,003), have been used from those surveyed in the Digital News Report 2017. The results show that a) Spain is the country with the highest incidental exposure rate among users who use social networks to be informed; b) it is more frequent when using Facebook and YouTube than on Twitter; and c) age, ideological orientation and the degree of interest in news influence this phenomenon.