Surfrider Foundation is a grassroots non-profit environmental organisation that is dedicated to the protection and enjoyment of the world’s oceans, waves and beaches, for all people, through a powerful activist network. Founded in 1984, the Surfrider Foundation has evolved into one of the largest non-profit grassroots organizations in the world with a volunteer-activist network dedicated to protecting our coasts and ocean. With more than 80 chapters, 100 student clubs and thousands of supporters, Surfrider's volunteers and activists are fighting over 100 active campaigns around the country at any time. Equipped with an activist model to defend our coasts, the organization has recorded nearly 800 victories since 2006. Surfrider's programs, including beach cleanups, volunteer water quality testing (Blue Water Task Force), and Ocean Friendly Gardens, remove approximately 170,000 pounds of trash from US beaches annually, and sample water quality in nearly 800 sites across the country. Surfrider has active international affiliates in affiliates in Japan, Argentina, Australia, Senegal, and throughout Europe. Sometimes referred to as Surf Rider Foundation (not correct, but not uncommon!)

SusGren is committed to the conservation of the coastal and marine environment and sustainable livelihoods for the people in the Grenadine Islands between Grenada and St. Vincent and the Grenadines.

Founded in 2014, Sustainable Ocean Alliance (SOA) activates young people, develops and implements innovative solutions, and ‘mobilizes an ocean workforce to restore the health of the ocean in our lifetime’. By supporting innovative startups, nonprofits, and grassroots campaigns through publicity, funding and grants, they are actively working on solving the problems faced by the oceans, including via technological and scientific solutions. As of 2021, they had become involved in 222 initiatives all over the world, each dedicated to restoring and sustaining the health of our ocean focusing on the following 5 general categories of solutions: Carbon (CO2) reduction and blue carbon; Pollution reductions and the circular economy; Blue Foods (Sustainable protein, fisheries and aquaculture); Ocean data, literacy and research; and Ecosystem preservation and restoration.

S.O.S is a non-profit organisation focused on marine conservation and ocean sustainability at a grass roots level.
'Our mission is to improve the health of the oceans around New Zealand through promoting and implementing sustainability at a grassroots level; to help in the creation of new marine reserves in New Zealand’s coastal waters; to educate and include the communities of the country in protecting the natural seafood resources we have for future generations to come; and to make it easy for people to make everyday sustainable choices.'

Sustainable Seas Trust (SST) is a science-based organisation that works to protect Africa’s marine resources for the benefit of all who live on the continent, supporting and connecting communities across Africa, via research, education, enterprise development and growing awareness about ocean conservation and plastic pollution. They build networks for sharing information and support focused on waste management. Through events such as the 2020 Second International Conference of the African Marine Waste Network and projects, SST brings like-minded and passionate people together, locally and internationally, to manage the issues of plastic waste in Africa.

The largest nature conservation and environmental organisation in Sweden with 170,000 members and 274 local branches across the whole country, SSNC has a significant programme addressing the sea and water,

The Swiss Cetacean Society-SCS is a non-profit organisation devoted to the preservation of marine mammals in their natural habitat. Based on the conviction that better scientific knowledge of the animals and their environment is essential to ensure efficient protection measures, SCS organises worldwide campaigns at sea for data collection on cetacean populations. This data is ultimately used in research. At the same time, SCS distributes general information about marine mammals to the Swiss public, encourages access to specialised training and organizes the logistics at sea of scientific and environmental programmes abroad.

The Tasmanian Conservation Trust's (TCT) purpose is to preserve and conserve all native wildlife and their habitat on all of Tasmania's land mass and its surrounding waters. TCT's marine programme focuses on preserving the local ocean, with campaigns such as monitoring industrial fish farming, invasive species.

The Animal Fund (TAF) was established in 2015 with its primary focus on protection of the ocean, dolphins and whales, now a marine conservation group which aims to educate and raise awareness on the threats facing our oceans and marine life, via campaigns, events, conferences, presentations and online media. It has offices in Monaco, Denmark, France and the UK. Education is TAF’s cornerstone. TAF works every day with schools and universities to inform about the whale’s importance to the ecosystem and our survival. As some of the biggest threats to marine life are plastic pollution and overfishing, TAF’s aim is to inform about alternatives to plastic and finding solutions to overconsumption.

The Bay Foundation (TBF)—also known as the Santa Monica Bay Restoration Foundation—is an environmental group founded to restore and enhance Santa Monica Bay and local coastal waters. TBF is staffed by science and policy experts who are passionate about understanding and protecting the Bay and the Bay watershed, and all the benefits that a healthy ecosystem can provide all those who use and enjoy it. A particular focus in their work is on the kelp forests in the Bay.

An online network of conservation projects, rated and reviewed by conservationists. The mission at The Conservation Network is to create a database of all the conservation projects around the world, including many marine conservation projects. The extensive information provided includes details about the project, location, costs (if any), and the activities involved, benefits, etc. A useful site for volunteers and people looking for work experience in conservation.

Founded in 1973 by Captain Jacques-Yves Cousteau, The Cousteau Society has more than 50,000 members worldwide. Under the leadership of President Francine Cousteau, the Cousteau Society continues the work of Jaques Cousteau in exploring and observing ecosystems throughout the world, and in the process have helped the understanding and appreciation of marine life. By establishing protected areas for endangered species and advocating on behalf of marine life, TCS has become a familiar name in marine conservation. Its French counterpart, L'Equipe Cousteau is based in Paris, France.