Construction will begin on Santa Carolina island in the picturesque Bazaruto archipelago off central Mozambique's Indian Ocean coast, said Rani's Mozambique representative Rui Monteiro.
"It will cost in the region of $100m ," he said.
Mozambique's long coastline, pristine beaches and warm climate are increasingly popular tourist destinations. The Bazaruto islands form a marine national park and are famous for their unspoilt scenery and coral reefs.
Rani is the biggest tourism investor in the country, with various resorts in other provinces. The Santa Carolina project will include a 100-room hotel, 24 apartments and vacation houses as well as a dock on the mainland.
Mozambique's tourism ministry this year approved projects worth more than $650m from January to September alone excluding the Bazaruto project, up 60% from the same period in 2009.
Visitor numbers to the country have increased from 711 000 to three million over the past six years.