Since mankind has navigated the world’s oceans, marine biofouling has been a persistent problem with several negative economic and environmental consequences. In modern times, the buildup of biofouling causes a significant reduction in vessel speed, leading to increased power consumption, higher costs of operation, and an increase in greenhouse gas emissions. Two of the most widely used protection strategies to combat this highly complex and dynamic phenomenon include the application of biocide containing anti-fouling (AF), or more environmentally friendly non-toxic fouling-release (FR) coatings. Traditional FR coatings utilize low surface energy components such as polydimethylsiloxane (PDMS), but often suffer mechanical failure and poor adhesion to the substrate. Recently, the development of a self-stratifying siloxane-polyurethane (SiPU) FR coating combined the desirable FR properties of PDMS containing materials, with the mechanically durable and tough attributes of a polyurethane. Several methods to improve on the FR properties of these coating systems involved the incorporation of hydrophilic moieties like polyethylene glycol (PEG), zwitterionic polymers, or carboxylic acid containing groups into the SiPU network, producing a heterogenous, amphiphilic surface. These types of amphiphilic surfaces have great potential to become a major component of the next generation of highly performing FR coatings. In this work, the use of non-reactive surface modifying amphiphilic additives (SMAAs) consisting of PDMS and PEG was explored as a viable method for further improvement of FR properties of SiPU coatings, while also maintaining coating integrity in marine environments. Additives with varying amounts of PDMS and PEG content were incorporated at several concentrations in both hydrophobic, and inherently amphiphilic SiPU FR coating systems. It was shown that these additives significantly alter the surface properties and morphology, producing surfaces that improve AF/FR performance against several model marine fouling organisms. The methodologies used for these types of coatings were also applied to a non-FR, polyurethane coating. This allowed for a more fundamental investigation into how these SMAAs are distributed throughout a coating system, and how FR properties arise. Lastly, commonly used FR coatings, including SiPUs, were applied to oil boom fabrics to observe their effect on FR properties and cleanability.