jats:titleAbstract</jats:title> jats:pParticularly Sensitive Sea Areas (jats:scPSSA</jats:sc>s) are a form of marine conservation measure established by the International Maritime Organization (jats:scIMO</jats:sc>) to protect the marine environment against damage caused by navigation. The politicisation of the jats:scPSSA</jats:sc> designation process and the shortcomings of the 2015 jats:scIMO</jats:sc> Revised Guidelines for the Identification and Designation of jats:scPSSA</jats:sc>s have been inimical to improving the jats:scPSSA</jats:sc> regime. This article first examines the law and practice of jats:scPSSA</jats:sc>s and discusses the shortcomings of the 2005 Guidelines. It then explores how politicisation outside and inside the jats:scIMO</jats:sc> has aggravated the institutional weaknesses of the jats:scPSSA</jats:sc> regime in three aspects: the relationships between Associated Protective Measures (jats:scAPM</jats:sc>s) and existing navigational measures; the links between the ecosystems and jats:scPSSA</jats:sc>s; and the lack of stringent jats:scAPM</jats:sc>s.</jats:p>