Registration services pertain to the technical coordination and inventory management of Internet number resources.

Services include: ARIN consists of the Internet community within its region, its members, a 7-member Board of Trustees, a 15-member Advisory Council, and a professional staff of about 50.

The BoT is responsible for determining the disposition of all revenues received to ensure all services are provided in an equitable manner.

Until this time, IP address registration (outside of RIPE and APNIC regions) was done in accordance with policies set by the IETF[7] by Network Solutions corporation as part of the InterNIC project.

The National Science Foundation approved the plan for the creation of the not-for-profit organization to "give the users of IP numbers (mostly Internet service providers, corporations and other large institutions) a voice in the policies by which they are managed and allocated within the North American region.".

[10] The initial Board of Trustees consisted of Scott Bradner, John Curran, Kim Hubbard, Don Telage, Randy Bush, Raymundo Vega Aguilar, and Jon Postel (IANA) as an ex-officio member.

[13] The countries in the ARIN service region are:[14] ARIN formerly covered Angola, Botswana, Burundi, Republic of Congo, Democratic Republic of Congo, Eswatini, Lesotho, Malawi, Mozambique, Namibia, Rwanda, South Africa, Tanzania, Zambia, and Zimbabwe until AfriNIC was formed.

ARIN formerly covered Argentina, Aruba, Belize, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Dutch West Indies, Ecuador, El Salvador, Falkland Islands (UK), French Guiana, Guatemala, Guyana, Haiti, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, South Georgia and the South Sandwich Islands, Suriname, Trinidad and Tobago, Uruguay, and Venezuela until LACNIC was formed.