Recent proceedings before the International Court of Justice (‘ICJ’, ‘Court’) have revived the doctrine of obligations erga omnes (partes) as a vehicle for rationalising forms of public interest litigation. It is now no longer seriously in doubt that States can rely on the erga omnes doctrine to establish standing to file complaints. This is an overdue clarification – but not a dramatic departure. In fact, this contribution shows that forms of public interest litigation were recognised already by the ICJ’s predecessor, the Permanent Court of International Justice (‘PICJ’). To show as much, the contribution offers a close reading of the PCIJ’s first judgment – the famous Wimbledon case – which accepted that applicants, irrespective of any individual legal interest, could initiate proceedings aimed at defending access to an international waterway. This early form of public interest standing was recognised on the basis of a generally worded jurisdictional clause, without any reference to concepts such as obligations erga omnes (partes). Looked at from a contemporary perspective, it is remarkable how pragmatically the PCIJ – in Wimbledon and beyond – handled questions of standing. Its approach holds much appeal as the international community of States now continues to seriously explore the possibility of public interest litigation.