In line with consumer awareness that a relationship between diet, health, and disease prevention exists, the research and development of new functional foods have been the target of many studies over the last years. The increasing ageing of populations, the decrease in quality of life due to stress, the high incidence of so-called modern diseases (cardiovascular disease, obesity, cancer, diabetes, and allergies) represent the driving forces in the quest for different foods and diets to promote healthy active ageing, improve well-being, and counteract the incidence of many diseases. The marine environment provides a huge source of many healthy foods, including seaweeds, which is an example of a marine product that has been part of the diet in several countries around the world. Additionally, marine specimens are also sources of a plethora of chemicals, many of them with biological properties and, therefore, called bioactive compounds. These chemicals can be extracted and incorporated in several food matrices leading to new potential functional foods. This chapter is a review summarizing those marine organisms with healthy properties that are consumed all over the world, as well as the potential of using marine organisms as sources of food ingredients towards applications in new functional foods. Recent findings on functional foods based on marine-derived ingredients are described and discussed.