Chicken Island in Krabi/Phang Nga — iconic rock shape, clear water, and a staple on Phuket jet ski and boat tours.
Quick answer: Chicken Island (Koh Kai Nok) sits near Poda and Tup Island. Tours from Phuket reach it by speedboat or on longer jet ski island hops — snorkeling, sandbar walks at low tide, and limestone scenery.