In the face of the difficulties of international climate diplomacy, ‘the invisible college of international lawyers’ has recently been called upon to devote more efforts ‘towards reviving the blunt edge of climate change-based national, regional, or international litigation, adjudication, and arbitration towards reaching sufficiency of climate pledges’ (Desierto 2019). This paper therefore reviews the use of international law arguments and remedies in climate change litigation, with a view to ascertain the related opportunities and constraints. In order to achieve this objective, this paper considers international legal practice in light of the typologies of climate change litigation identified in the literature (Peel and Osofsky 2015; Setzer and Vanhala 2019). This literature typically distinguishes between so-called ‘proactive’ litigation — initiated in order to engender policy change, for example, asking for the adoption or reform of legislation; and ‘reactive’ litigation — initiated to resist such change, for example, challenging the adoption of new or reformed legislation. Reactive litigation has long been common at the international level, whereby investors have instigated international investment disputes to resist reforms of renewable energy subsidies, with alternate fortunes (Baetens 2019). Proactive litigation at the international level, instead, has been rarer and more recent. It has largely focused on the use of international human rights remedies for complaining over states’ failure to mitigate climate change, and/or over states’ failure to address the impacts of climate change (Savaresi and Auz 2019). The possibility to make greater use of other international law instruments and remedies to address both issues has been at the centre of much scholarly speculation. Already in 2007, Faure and Nollkaemper suggested that, even though they faced ‘significant hurdles’, international liability suits could help to put pressure on states to reduce emissions (Faure and Nollkaemper 2007, 172). Much literature has considered the role of the law on state responsibility in this connection (Tol and Verheyen 2004; Verheyen 2005; Voigt 2008; Wewerinke 2019). No inter-state legal suits have however been lodged so far. Similarly, international judicial bodies, such as the International Court of Justice (Stephens 2019) or the International Tribunal on the Law of the Sea (McCreath 2020), could be asked to adjudicate over matters of compliance with international climate obligations on the basis of customary international law (Bodansky, Brunnee, Rajamani 2017). Again no inter-state legal suits have been lodged on this basis to date. This paper reviews these international litigation scenarios and ascertains opportunities and constraints, in light of developments occurred in recent years. Paraphrasing Bierly (Bierly, 1928), the paper concludes that, given the present state of international climate diplomacy, international litigation is neither a chimera nor a panacea, but represents one means at our disposal for delivering better climate protection.