Call it the flip-flop meter: the amount of time that passes between touching down on an island runway and the merciful moment a weary traveller can finally kick off their lace-ups for island-appropriate footwear.

At the recently opened Regent hotel on Vietnam’s Phu Quoc Island, a triangle-shaped stretch of protected jungle and beaches in the Gulf of Thailand, it’s just over half an hour since I’ve cleared immigration and I’m already barefoot, dressed in linen and adjusting to island time in a Terrace Pool Villa.