Vietnam's water experiences are among the best-organised in Southeast Asia. Ha Long Bay overnight junk cruises — moving through a seascape of 2,000 limestone karst islands, swimming in the emerald water between rock towers, and kayaking into sea cave lagoons — are the country's most iconic on-water experience. Mekong Delta boat tours from Can Tho — small motorised wooden boats threading through channels lined with water coconut, stopping at floating markets and riverside noodle stalls — offer the southern freshwater counterpart. Hội An lantern boat evening releases on the Thu Bon River, Perfume River sunset boat excursions from Huế, and the cave boat tour into Phong Nha's 7-kilometre illuminated river cavern extend the water register across the country's length.