"Cyberspace" is often treated as a new domain of State activity in international legal discourse. This has led to the assumption that for international law to apply to cyber operations carried out by States or non-State actors, "cyber-specific" State practice and opinio juris must be demonstrated. This article challenges that assumption on five different bases. First, it argues that rules of general international law are generally applicable to all domains, areas, or types of State activity. In their interpretation and application to purported new domains, limitations to their scope of application cannot be presumed. Second, this article demonstrates that the concept of "domain" is not aimed at excluding certain domains from international law’s scope of application. Third, in any event, cyberspace is not a domain or a space, in the way that land, air, sea, or outer space are. Rather, it is a combination of multilayered information and communications technologies operating across different domains. Fourth, and relatedly, international law is technology-neutral, in that it applies to all technology unless stated otherwise. Fifth, the framing of certain international legal rules as policy recommendations cannot displace existing international law. On those bases, we conclude that existing international law applies as a whole and by default to States’ use of information and communications technologies.