Central to the International Court of Justice’s decision in Whaling in the Antarctic (Australia v Japan) is the finding that whaling permits issued under JARPA II do not fall under the ‘scientific research’ exception found in article VIII of the International Convention for the Regulation of Whaling (ICRW). An argument can be made, however, that the manner in which the majority of the Court interpreted article VIII is inconsistent with the approach to interpretation set out in article 31 of the Vienna Convention on the Law of Treaties. Importantly, the majority’s interpretation of the phrase ‘for the purposes of’ in article VIII, as only requiring consideration of the ‘reasonableness’ of the design and implementation of JARPA II, is unsupported by the ordinary meaning of those terms and has resulted in the dilution of what was otherwise the core restriction on states’ ability to take and kill whales under article VIII.