According to Resolution XXIII-14 membership in ICG/NEAMTWS includes:

- Member States of the IOC bordering the north-eastern Atlantic and those bordering and within the Mediterranean Sea and connected seas. 

- Observers from other IOC Member States.

- Invited observers from other organizations (including NGO’s), programmes and projects in accordance with the IOC rules and procedures.

Member States establish Tsunami National Contacts that represent the country in the coordination of international tsunami warning and mitigation activities. 

Member States
Albania
Algeria
Belgium
Bulgaria
Cape Verde
Croatia
Cyprus
Denmark
Egypt
Estonia
Finland
France
Georgia
Germany
Greece
Iceland
Ireland
Israel
Italy
Lebanon
Libya
Malta
Mauritania
Monaco
Morocco
Netherlands
Norway
Poland
Portugal
Romania
Russian Federation
Slovenia
Spain
Sweden
Syria
Tunisia
Turkey
Ukraine
United Kingdom

Observer Member States
Cameroon
Canada
Cote d'Ivoire
Guinea
Switzerland
Togo
United States of America 

Invited Observers
United Nations organizations

International Hydrographic Organization (IHO) 

International Telecommunications Union (ITU) 

United Nations Environment Programme, Mediterranean Action Plan (UNEP/MAP) and Regional Activity Centre for Priority Actions Programme (PAR/RAC)

United Nations Institute for Training and Research (UNITAR) 

United Nations International Disaster Reduction Strategy (UNISDR)

United Nations Platform for Space-based Information for Disaster Management and Emergency Response (UN-SPIDER) 

United Nations University,  Institute for Environment and Human Security (UNU-EHS)

World Meteorological Organization (WMO) 

Other intergovernmental organizations

European Commission, Directorates-General for Environment - Civil Protection; Information Society and Media; Research; and Joint Research Centre

Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) 

Other invited organizations

EuroGOOS 

European Sea Level Service (ESEAS) 

Euro-Mediterranean Seismological Centre (CSEM/EMSC) 

International Ocean Institute (IOI) 

Monitoring Network System for Systematic Sea Level Measurements in the Mediterranean and Black Sea (MedGLOSS)

World Agency of Planetary Monitoring and Earthquake Risk Reduction (WAPMERR)