This study examines how corporate water reporting practices evolved among Thai listed companies in the Agro and Food industry between 2000 and 2022. Drawing on archival documents, interviews, and participant observations analysed using qualitative content analysis and thematic analysis guided by Actor-Network Theory (ANT), the study explores how both human and non-human actors (i.e., regulators, report preparers, laws, disclosure templates, and environmental events) interacted to shape reporting practices over time. The analysis identifies four analytical phases: (1) Early Water Disclosure in Corporate Reporting (2000-2006), (2) Framing Water in CSR Reporting (2007-2014), (3) Institutionalising Water in Sustainability Reporting (2015-2020), and (4) Integrating Water in One Reporting (2021-2022). Across these phases, water disclosure gradually shifted from minimal, compliance-driven mentions to a more structured, performance-based and integrated component of Thailand’s One Report system. Through the lens of ANT’s translation moments, namely problematisation, interessement, enrolment, and mobilisation, the findings suggest that changes in water reporting emerged through gradual negotiations among actors rather than through linear regulatory enforcement alone. By offering a longitudinal analysis of reporting change in an emerging economy context, the study illustrates how local regulatory integration (the One Report) transformed water from a voluntary CSR topic into a more formalised disclosure category.