Thai authorities are racing to finalise rescue plans to retrieve 12 boys and their football coach from a Thailand cave before storms forecast for the end of the week, after which an extraction will become “almost impossible” for months, according to one coordinator of the international rescue effort.

The boys, none of who can swim, are being trained in how to breathe through diving masks but none have made any attempt to get through the water hemming them in.

Authorities said they appeared mentally and physically healthy after receiving food and water supplies, but were yet to speak to their parents after the waterproof seal of a phone sent into the narrow, muddy cave system was breached, ruining the device.