The plant's operator is planning to release 7,800 tonnes of water into the Pacific Ocean.
The previous three rounds of treated water discharge from the Fukushima nuclear power plant were conducted in August, October and November 2023.
Japan started releasing part of the estimated 1.34 million tonnes of Fukushima treated water into the ocean in August 2023 despite an outcry from neighboring countries and local fishermen. In total, more than 31,000 tonnes of mildly radioactive water will be released during the 2023 fiscal year, which ends March 31. The entire process is expected to take at least 30 years.