The IMarEST is an international membership body and learned society that brings marine engineers, scientists and technologists together into one professional body. 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 if marine professionals worldwide.

Members are able to plan professional registration (such as Technician, Incorporated, Registered or Chartered status). Education is supported through MLA College (Plymouth) which delivers distance e-learning.

The IMarEST is an NGO with consultative status at the International Maritime Organisation (IMO) observer status at the Intergovernmental Oceanographic Commission and International Hydrographic Organisation plus special consultative status with the Economic and Social Council of the United Nations (ECOSOC)