Ko Yao Yai, or "Big Long Island", running about 30 kilometres in length from top to bottom, sits halfway between Phuket and Krabi in the middle of Phang Nga Bay. Though only a 25-minute speedboat trip from Phuket’s east coast, this long, narrow island ringed with thick mangroves and white-sand beaches has somehow avoided becoming another hectic island resort. It’s more than twice the size of neighbouring Ko Yao Noi, but tourism development here lags behind its sister island.