As oil and gas operations transition into deeper waters and more technically demanding basins, the integrity of subsea infrastructure has never been more critical. This article examines the role of hydrostatic testing and fluid preservation as a proactive asset-protection strategy. While hydrotesting is a standard verification of mechanical integrity, the use of untreated seawater or improperly managed fresh water introduces significant risks, including oxygen-driven pitting corrosion and Microbiologically Influenced Corrosion (MIC). As projects move into deeper waters and more stringent environmental jurisdictions, traditional methods of managing multiple discrete chemicals can introduce operational complexity and compatibility risks in some projects. This article explores the shift toward multifunctional preservation chemistries and highlights the importance of technical capability and logistical resilience in project execution. Drawing on hydrotest project examples from Australia and Northwest Africa, the article illustrates how a holistic preservation strategy, including the use of chemistries such as SLB’s Hydrosure™ range, can support long-term asset integrity, simplify operational execution, facilitate environmental compliance, and help safeguard the intended design life of subsea infrastructure.