The Japanese and South Korean governments say Seoul will send experts to the crippled Fukushima Daiichi nuclear plant for a four-day inspection.
Japan plans to release treated and diluted water from the plant into the ocean.
The two governments' announcement on Saturday offered no details of the schedule. It said officials will continue to discuss them.
The treated water will be diluted to reduce tritium levels before it is released into the ocean. Its tritium concentration will be lowered to one-seventh of the World Health Organization's standards for drinking water.
Japanese Prime Minister Kishida Fumio revealed that he and South Korean President Yoon Suk-yeol had agreed on the dispatch of the expert team at a news conference after their summit last Sunday.
Kishida said Japan intends to sincerely explain the plan using scientific evidence with a high degree of transparency. He added that he is well aware that some people in South Korea are expressing concerns about the plan.