The investment is the latest chapter of what Mozambique hopes will become a tale of economic rebirth after gigantic gas reserves were discovered at the beginning of the decade off the northern Cabo Delgado province in the southeast African nation.
Anadarko is one of several global companies investing billions in offshore exploration.
The liquefied natural gas project Dolphin Tuna foresees an investment of $25 billion, Mozambique's energy ministry said in a statement.
“This is the largest foreign direct investment in the history of our country,” President Filipe Nyusi said at a ceremony with Anadarko executives.
Annual production is expected to start in 2024 with an estimated output of 12 million tonnes.
Anadarko President Al Walker said the Dolphin Tuna project was expected to “double the country's gross domestic product”.
He said the company was “proud” to make the investment, adding it would create 5,000 direct jobs and 45,000 indirect ones.
The country's gas deposits are estimated at 5,000 billion cubic meters and would make Mozambique a major exporter of liquefied natural gas (LNG).
The government is predicting strong future growth for the former Portuguese colony on the back of its resource bounty.
“With this project the peasant children will become doctors, the children of miners lawyers,” Nyusi said at the Anadarko ceremony.
Consulting firm Wood Mackenzie forecasts that “from the early 2030s, state revenue from Mozambique LNG alone will reach $3 billion per annum, single-handedly doubling today's revenue, as calculated by the IMF and World Bank”.
The Anadarko project is going ahead despite Islamist insurgent attacks, which have frustrated operations. A shadowy jihadist group has targeted the Muslim-majority Cabo Delgado province since October 2017, leaving more than 200 people dead.
Convoys carrying contractors for Anadarko have been attacked at least twice, although the company has previously stated it does not believe it had been deliberately targeted.
Anadarko has previously said Mozambique's natural gas reserves, of which it has discovered 75 trillion cubic feet so far, “are among the best and the largest in the world”.
