The ocean has become a repository for an increasing quantity of plastics and microplastics. This has been matched, in recent years, by growing awareness of the social, economic and environmental impacts that this phenomenon is causing. There is widespread recognition that urgent action is required to reduce the leakage of plastics to the ocean, but that there is no simple solution. It is clear that the traditional linear production, use and disposal model for conventional plastics is not sustainable and results in unacceptable harm. This requires the development and implementation of more closed-loop, or circular, production models. But there is scope for assessing whether there are alternative solutions that minimise the use of conventional plastics for applications in which they are not essential. The purpose of this study was to assess the potential of replacing conventional plastics with alternative materials in certain applications, as part of a wider strategy of reducing marine plastic litter and microplastics. The target audience is governments and businesses. This may appear a daunting task, given the ubiquity of plastics in our daily lives, described in Chapter 2, so it seemed sensible to identify certain categories of plastics that may prove more amenable to reduction or replacement. Following an assessment of the most common items reported in field surveys (Chapter 3) it was decided to focus part of the study on 'single-use' plastic waste from single-use packaging and consumer products intended for short-term use, such as food and drink containers, given the preponderance of these categories in surveys of ocean plastics, especially in shoreline debris. Another common feature of microplastics identifed in surveys of biota, sediments and seawater is the abundance of micro-fbres. Micro-fibres on shorelines, especially near urban centres, consist mostly of textile fibres and this provided a second focus for the study.