Energy company, Anadarko gas found more than of 300 net feet of natural gas pay in two areas in its Atum exploration well in the Rovuma Basin.
It appears to be connected to a recent discovery about 10 miles northwest of the area where the new natural gas was found, said the company.
Africa could become a crucial supply point for China and other countries with expanding economies in Asia.
The two discoveries, and the fact that they are apparently connected, would make them Anadarko's second major natural gas discovery offshore from Mozambique, the company said.
The company estimated that the new discovery holds 10 trillion to 30 trillion cubic feet of recoverable natural gas. Its total gas in that area near Mozambique is between 30 trillion and 60 trillion cubic feet, the company said.
Anadarko will immediately begin four wells to appraise the find.
The Atum well was drilled to a total depth of 12,665 feet, in water 3,285 feet deep.
Shares of Anadarko Petroleum Corp. fell 76 cents to USD 62.99 in midday trading.