The move, more than a decade after the nuclear disaster, will deal another blow to Fukushima’s fishing industry, which has opposed such a move for years.
Work to release the water will begin in about two years, the government said, and the whole process is expected to take decades.
“On the premise of strict compliance with the regulatory standards that have been set, we select ocean release,” the government said in a statement after relevant ministers formalized the decision.
The water must be filtered again to remove harmful isotopes and will be diluted to meet international standards before any release.
The decision comes about three months before the postponed Olympic Games to be hosted by Tokyo, with some events planned almost 56 kilometers from the destroyed factory.
The removal of contaminated water from the Tokyo Electric Power-operated Fukushima Daiichi plant has proved to be a thorny issue for Japan as it has been pursuing a decades-long decommissioning project.