The Union of Comoros is a small island nation located in the Indian Ocean between Madagascar and mainland Africa . The Comoros ( ; , ' ) , officially the Union of the Comoros ( Comorian : Udzima wa Komori , , ' ) is an archipelago island nation in the Indian Ocean , located off the eastern coast of Africa , on the northern end of the Mozambique Channel , between northeastern Mozambique and northwestern Madagascar . Other countries near to the Comoros are Tanzania to the northwest and the Seychelles to the northeast .