Planet earth’s defining feature is the ocean and it is the reason that life exists. It produces oxygen, absorbs carbon dioxide, and contributes to freshwater renewal. It connects countries and cultures and supports ecosystems that bridge national boundaries. Nations are increasingly looking to the ocean to meet the needs of their people, particularly coastal communities and islands. Some are looking at their large lakes and rivers to do the same. This MOOC introduces the key activities that take place in, and influence, coastal and marine space, for example, coastal and climate adaptation, tourism, shipping and port infrastructure, waste, and maritime security.