DMI is a higher learning institution under the supervision of the Ministry responsible for maritime affairs in the United Republic of Tanzania. DMI was formed by cabinet Resolution on 3rd July 1978 and started as a Project under the supervision of the Norwegian Agency for Development Cooperation (NORAD) for the purpose of training employees of the National Shipping Company (TACOSHILI). At that time it was operating under the name Dar es Salaam Maritime Training Unit (DMTU). DMTU acquired the name DMI after its establishment by the Act of Parliament No. 22 of 1991 to cater for greater needs of shipping industry.

In 2003 Tanzania was found to be giving full and effective implementation of the Revised STCW Convention of the International Maritime Organisation (The so called IMO White List), DMI started to offer seafarers education and training in accordance with acceptable international standards. DMI started to offer seafarers education and training at the level of Chief Engineer/Second Engineer and Master/Chief Mate officer's Courses in 2007. Regarding academic courses, DMI was accredited by NACTE in 2003 to offer National Technical Awards at the level of Diploma and later in 2013 at the level of bachelor degree. Therefore, DMI offers programmes accredited by IMO, NACTE (NTA Level 4-8) and SUMATRA (Certificate of Competency-CoC), and other programmes in affiliation with CILT (Logistics & Transport) and ABMA (Shipping and Logistics).

In November 1996, the 6th Commission of the East African Community Secretariat pronounced DMI as the Centre of Excellence for Maritime Education and Training in East Africa after undergoing a thorough audit process and there after in 2011 another thorough audit process for the same purpose was carried out. The centre has qualified personnel and provides quality education which suits market needs in the aspect of being employed and self employment in the maritime industry.