Phoebe Okowa has been elected as a judge of the International Court of Justice (ICJ). She is a member of the United Nations International Law Commission (since 2023) and has served on the Legal Committee of the Commission of Small Island States and International Law (since 2021). She holds a longstanding academic position at Queen Mary University of London, where she has been a professor of public international law since 2002, previously serving as a reader and senior lecturer. Her teaching experience includes appointments as a global visiting professor at New York University School of Law and lecturer in law at the University of Bristol.

Academically, Okowa earned her Bachelor of Laws (LLB, First Class Honours) from the University of Nairobi, followed by a Diploma in Legal Practice at the Kenya School of Law. She then completed a Bachelor of Civil Law and a Doctor of Philosophy (PhD) in International Law at the University of Oxford. She is an advocate and member of the Kenyan Bar.

Judge Okowa has contributed extensively to international legal scholarship, including publications on state responsibility, natural resources in conflict zones, environmental law, and case analyses of the International Court of Justice. She has also served as a member of the Permanent Court of Arbitration (2017–2022). She has been involved in research projects funded by the Arts and Humanities Research Council and the Harold Hyam Wingate Foundation. In 2022, she was awarded the Elder of the Order of the Burning Spear for services to Kenya and the wider international community.