The Institute of Marine Engineering, Science & Technology (IMarEST) is an international membership body and learned society bringing together marine engineers, scientists and technologists and supporting them through every stage of their career. The largest marine organisation of its kind, it spans 128 countries and works to promote the scientific development of marine disciplines, providing opportunities for the exchange of ideas and practices and upholding the status, standards and expertise of marine professionals worldwide.

Membership provides the opportunity to gain professional registration, such as Technician, Incorporated, Registered or Chartered status.

The IMarEST is an NGO with consultative status at the International Maritime Organization (IMO), 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) and it has special consultative status with the Economic and Social Council of the United Nations (ECOSOC).