Founded in 1889 and granted a Royal Charter in 1933, the IMarEST are the international professional body and learned society for all marine professionals. With a worldwide membership of marine engineers, scientists and technologists based in over 128 countries, the IMarEST provides levels of membership for everyone, from professionals seeking to become Chartered or gaining other Professional Recognition, to those just starting out in their careers, or studying in education, or those interested in supporting the work of the IMarEST.

The IMarEST are an NGO with consultative status at the International Maritime Organization (IMO) and observer status at the Intergovernmental Oceanographic Commission, International Hydrographic Organization, the London Convention/London Protocol (LC/LP) and the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP). The IMarEST have special consultative status with the Economic and Social Council of the United Nations (ECOSOC), which facilitates its access to other international intergovernmental meetings where their specialized marine expertise is of particular use, e.g. the United Nations meetings on Areas Beyond National Jurisdiction, the Intergovernmental Panel on Climate Change (IPCC) and the work of the International Seabed Authority on marine mining.