The record bid, by a team of mainly freshwater divers based in the inland city of Pune, was organised by local businesses Chrysalis Entrepreneur Forum and Absolute Scuba, and took place at the Coral Grand Resort in Sairee Beach.
The team had spent six months preparing for their bid, as they were not all qualified divers or even swimmers at the outset, and had little experience of salt water before arriving on Koh Tao.
The divers, who ranged in age from 8 to 58, sang their national anthem and said a prayer before creating a 140m-long chain under water.
Their record breaks that set by 173 Italian divers on Elba in 2015. In October last year divers based in Cyprus claimed to have set a new record by forming a 278-diver chain, but Guinness World Records told Divernet that four months after the event it was still waiting for further supporting evidence that it had requested, so had been unable to ratify that claim.
Divers still have some way to go to emulate air-breathing human chains. That record was set in 2004, when five million people joined hands to form a 652-mile chain in Bangladesh.
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