Modern competitive swimming is a highly structured, organized, codified and regulated sport. This has not always been the case. The aim of this thesis has been to examine the long-term development of competitive forms of swimming throughout the periods between the late sixteenth and early twentieth centuries. Despite some recent historical analyses, the emergence of swimming as a modern competitive sport is an under-researched topic. There are no sociological analyses relating to the development of competitive swimming and significant gaps within much historical research. This thesis has been conducted from a sociological perspective in order to test the relative adequacy of Norbert Elias’s concept of sportization. Figurational sociologists have often examined the concept of sportization in relation to the development of contact sports such as boxing and rugby. Some authors have sought to criticize figurational sociologists for over-emphasizing issues relating to the increasing control of violence when examining the development of such activities. In this manner, there is scope to contribute to existing empirical and theoretical knowledge by testing the relative adequacy of the concept of sportization in relation to the long-term development of the predominantly non-contact sport of competitive swimming. To this end, data have been examined from a range of documentary sources. Various swimming-based texts, treatises, periodicals and magazines were examined at the British Library and Colindale Newspaper Library in London. The original minute books of the Amateur Swimming Association and its predecessor bodies have also been analyzed. In addition, a range of digitized source material has been examined from several electronic databases. It has been argued that the development of modern competitive swimming was an unplanned and unintended outcome resulting from the complex interweaving of wider social processes in England throughout the periods between the Middle-Ages and the early twentieth century. The earliest reported swimming contests took place in the eighteenth and early nineteenth centuries in the form of a cash wager between two or more individuals. These events were less structured and regulated than modern forms of competitive swimming. Betting upon the outcome of such events was deemed to be an appropriate means to experience heightened levels of tension-excitement within the context of an emerging society in which people were increasingly expected to demonstrate greater self-control over their behaviour and emotions. More organized forms of competitive swimming gradually emerged during the nineteenth and early twentieth centuries. The emergence of an increasingly complex network of clubs, societies and associations at local, county, district and national levels facilitated such developments and contributed to the emergence of standardized rules and regulations within the emerging sport of swimming. Such developments have been explained in relation to ongoing processes of state-formation, pacification, lengthening chains of interdependence and a gradual lowering in the threshold of repugnance within England in the period between the Middle-Ages and the early twentieth century. In this manner, it has been argued that the concept of sportization is an appropriate theoretical framework for explaining the long-term development of the modern non-contact sport of competitive swimming.