This paper explores the self-presentation and online discursive practices of grassroots hacker collectives on both sides of the Russia-Ukraine conflict, within a larger geopolitical climate of a contested globalisation agenda and a growing fear of cyber warfare. Both pro-Russian and pro-Ukrainian hacker groups engage in DDoS attacks, malware distribution and leaking information stolen from the opposing side. They also use social media to craft public presences and enter the broader political discourse around the conflict. The paper uses online ethnography to observe and examine the Twitter posts of prominent pro-Russian and pro-Ukrainian hacker collectives. The analysis reveals key modes of the groups’ online practices and key discursive themes in the context of the conflict, such as political activism, information warfare, hacker ethics and patriotism. The study elucidates how these groups use their social media presence to construct a ‘patriotic hacker’ identity for themselves, to delegitimise their opponents and ultimately to connect to the broader mediated discourse of the conflict, where issues of patriotism, sovereignty and nationhood are contested.