RIMES evolved from the proposal by the Royal Thai Government to the Special ASEAN Leaders’ Meeting on 6 January 2005 and subsequently to the Phuket Ministerial Meeting on Tsunami Early Warning Arrangement from 28-29 January 2005 to establish a tsunami early warning system in a multi-hazard framework for Southeast Asia and the Indian Ocean. In March 2005, Cambodia, China, Lao PDR, Myanmar, Philippines, Thailand, and Vietnam agreed to cooperate to establish a regional end-to-end multi-hazard early warning system, facilitated by the Asian Disaster Preparedness Center (ADPC), with China and the Philippines as resource partners. In 2006, Bangladesh, Maldives, and Sri Lanka joined RIMES. The countries adopted a regional program to establish and operate the system, as well as constituted a Regional Steering Committee (RSC) of national focal points for hazard early warning to provide policy guidance and a Regional Technical Committee of experts to provide technical guidance. Myanmar was elected as RSC Chair, and Sri Lanka and Thailand as Vice-Chairs.

Through projects implemented by ADPC from 2005-2010, the United Nations Economic and Social Commission for Asia and the Pacific (UNESCAP) supported the development of the tsunami early warning system and the establishment of a regional early warning facility located at the campus of the Asian Institute of Technology (AIT) in Pathumthani, Thailand. China and the Philippines provided technical support through the Regional Technical Committee, while the Danish International Development Agency (Danida) supported the development of hydro-meteorological early warning support capability to national meteorological and hydrological services of collaborating countries.

In 2007, Mauritius, Mongolia, and Yemen joined, and Comoros, India, Kenya, Madagascar, Mozambique, Pakistan, Somalia, Seychelles, Tanzania, and Timor-Leste expressed interest to participate in the regional cooperation. In January 2008, the first meeting of the Regional Steering Committee, held in Bangkok, agreed to take responsibility to sustain the regional arrangement, in response to ADPC’s sustainability concerns when the projects supported by UNESCAP and Danida end. The RSC established a Working Group consisting of Lao PDR, Maldives, Myanmar, Sri Lanka, and Thailand, with Maldives as Secretariat to the Working Group, tasked to evolve and implement a sustainability action plan.

Subsequent meetings of the Working Group developed a project for sustaining the early warning system, which received funding from UNESCAP, with the Secretariat, Maldives Meteorological Service, as implementing agency; drafted a cooperation agreement for a Regional Integrated Multi-Hazard Early Warning System (RIMES) that would fully own, operate, and manage regional early warning arrangements; and identified financial mechanisms for sustaining RIMES.

In November 2008, the second RSC meeting, held in Hyderabad, urged collaborating countries to sign the RIMES Cooperation Agreement, and agreed to establish a Program Unit, co-located with the regional facility for early warning, with delegated powers to manage the day-to-day operation of the regional facility.

On 30 April 2009, the Regional Integrated Multi-Hazard Early Warning System for Africa and Asia was formally established, with the signing of the RIMES Cooperation Agreement by Cambodia, Comoros, Lao PDR, Maldives, and Seychelles. On 1 July 2009, RIMES was registered with the United Nations under Article 102 of the UN Charter as an international and intergovernmental organization, owned and managed by its Member States, for the generation and application of early warning information. Other countries will become RIMES Member States as and when the process of government reviews and approval of the RIMES Cooperation Agreement is completed.

RIMES assumed full responsibility of the regional facility on 1 January 2010, with the termination, on 31 December 2009, of the transition agreement with ADPC. Assets were transferred to RIMES by Danida in November 2009, and by UNESCAP in October 2010.