Japan's last commercial hunt was in 1986, but it has continued whaling for what it says are research purposes.
The hunts come after Japan's withdrawal from the International Whaling Commission, a move slammed by anti-whaling activists but welcomed by Japanese whaling communities.
According to Evening Standard, The Fishery Agency of Japan has set a strict catch quota for commercial whaling, and this year it amounts to 227 whales which includes 52 minkes, 150 Baird's beaked whales and 25 sei whales.
AMCS and the International Fund for Animal Welfare has released a legal opinion from an international law expert showing Japan's commercial whaling opens the country to legal action.
In as early as the 1990s, scientist Alfred Berzin was contrasting Japan's practice of whaling in the Antarctic with Soviet Russia's project to kill some 180,000 humpbacks across oceans in the southern hemisphere.
But despite global criticism, in 2016, commercial whalers killed 333 minke whales, according to Japan's Institute for Cetacean Research. Japan abandoned commercial whaling in 1988.
He said he hoped whale meat would be reasonably priced so that it will gain popularity in the long term instead of becoming an expensive delicacy for a limited clientele.
Japanese demand for whale meat has always been on the decline and the industry is already being subsidised.
Many animal rights activists sharply criticize Japan's resumption of whale hunting.
"My heart is overflowing with happiness, and I'm deeply moved", AFP quoted Yoshifumi Kai, head of the Japan Small-Type Whaling Association, as having noted while addressing a crowd of several dozen politicians, local officials and whalers.
Whale meat was a key source of protein in the immediate post-World War II years in Japan, when the country was desperately poor. The ministry says the ships will only operate in Japan's territorial waters and exclusive economic zones.
A permanent commercial whaling ban might sound like an ordinary step, but the IWC's goal since 1946 has been "the orderly development of the whaling industry".
The ships would go on to catch another, Kyodo News Agency reported. Whaling is a small industry in Japan, employing around 300 people, and five vessels are expected to set sail in July. One vulnerable population living in Japan's EEZ which may be affected are common minke whales (Balaenoptera acutorostrata), which are genetically distinct and possibly number fewer than 5,500.
But the Humane Society International ripped into the decision to allow commercial whaling. "Whale meat is a traditional food in Japan and I would like many people to try and develop taste for it, especially younger people". But whale was quickly replaced by other meats. Some commercial whalers are unsure if there is a big enough market for whale meat for their industry to survive.
"We were able to catch a good whale".