Resource: Professional Societies
- Global Witness
- Gordon and Betty Moore Foundation
- Got Green
- Great Barrier Reef Foundation
- Great Minds in STEM
- Great Minds in STEM
- Green Ideas For Tourism for Europe
- Greenaction
- Greenpeace
- Greenpeace Environmental Justice Campaign
- GreenWave
- Grist
- Guild of Natural Science Illustrators
- Gulf Coast Center for Ecotourism & Sustainability
- Gulf of Maine Research Institute
- Half Initiative
- Hawai'i Department of Land and Natural Resources
- Hawai‘i Women in Filmmaking
- Hawaii Aquaculture & Aquaponics Association
- Hawaii Ocean Watch
- Hedgebrook
- Hellenic Institute of Maritime Archaeology
- Her Film Project
- Heritage Victoria (Australia)
- Herring Gut Coastal Science Center
- Horror Writers Association
- Houston Underwater Photographic Society
- HudsonAlpha Institute for Biotechnology
- Human Microbiology Institute
- I Am Water Foundation
- Idaho Department of Environmental Quality
- IEEE Oceanic Engineering Society
- ILASOL
- Illinois Department of Natural Resources
- Indiana Aquaculture Association
- Indiana Department of Natural Resources Indiana Department of Natural Resources
- Indigenous Clean Energy
- Indigenous Education Institute
- Indigenous Environment Network
- Inland Ocean Coalition
- Institute for Molecular Virology
- Institute for Ocean Conservation Science
- Institute of American Indian Arts
- Institute of Biomedical Science
- Institute of Fisheries Management
- Institute of Marine and Environmental Technology
- Institute of Marine Engineering Science and Technology
- Institute of Marine Engineering, Science and Technology
- Institute of Medical Illustrators
- Institute of Nautical Archaeology