This article explores the critical issue of detainee protection in the complex landscape of contemporary non-international armed conflicts and counterterrorism operations. It examines the interplay between international humanitarian law and international human rights law, highlighting the challenges in their application and interpretation. The article delves into the contemporary challenges faced in protecting detainees, including the involvement of non-state armed groups, extraterritorial detention practices, administrative detention, and the impact of counterterrorism measures. It proposes a multifaceted approach to enhancing detainee protection, encompassing strategies for strengthening compliance with the legal framework, addressing the specific needs of vulnerable groups, and promoting best practices and capacity-building. The article argues that a comprehensive and contextualised approach, grounded in the principles of humanity and human dignity, is essential to effectively safeguard the rights and well-being of detainees in these challenging contexts.