The seven Koreans, named as Bohwa Choi, 29, Song Min Joo, 27, Lee Jung Sun, 29, Choi Jung Sun, 28, Eunjoo Kwak, 30, Joo Seung Hyo, 31 and Anh Yong Soo, 31, were all staying at the Baan Thai Hotel in Patong when they came down with bouts of vomiting and diarrhoea.
They were sent to Patong Hospital, then transferred to Phuket International Hospital to be treated.
Deputy Superintendent of Kathu Police Station, Pol Lt Col Kittipong Klykeaw, said the seven were on a tour and stopped for lunch at a seafood restaurant in Phang Nga Province.
There they tucked into a hearty feast of the prehistoric sea creatures. By evening all were ill. Treatment at Phuket International Hospital fairly quickly put them right.