Eni signed the deals with the Kenyan government for blocks in the deep and ultra-deep waters off the Kenyan coast.
"Eni's entry into Kenya reinforces its presence in the exploration of the frontier basins of East Africa, which has recently led to the discovery of significant volumes of natural gas in the deep waters of Mozambique," the company said in a statement.
Eni gave no estimates of the expected reserve potential in the offshore blocks.
Tullow Oil said in May its Ngamia-1 prospect in Kenya encountered more than 325 feet of net oil pay across multiple reservoir zones.
Kenyan President Mwai Kibaki said Tullow's discovery marked "the beginning of a long road to make our country an oil producer."
Eni, under the terms of the deal, serves as the operator of the three offshore blocks, which cover an area of more than 13,500 square miles.