Several companies in Nha Trang offer day-trips to a selection of islands, including a stop for snorkelling and a seafood lunch on board – all for around $6–8 per person. However, to fully enjoy the day, you’ll need to fork out for several extras if you don’t want to sit on the boat and wait till everyone comes back. Some boat rides, particularly those booked through backpacker guesthouses, can be quite wild and alcohol-fuelled, while other operators run gentler tours.
On a typical island day tour, you’ll be picked up from your hotel, taken to Cau Da Wharf, 6km south of the town centre, and shuffled on to one of many boats jostling in the harbour. As the boat casts off at around 9.30am, you’ll pass beneath the cable car to Hon Tre, then chug between islands for about half an hour to Hon Mun (Black Island), named after the dark cliffs that rear up from it. There’s no beach to speak of on Hon Mun, but the island boasts one of the best places for snorkelling in the area, with some great coral. Boats hang around for an hour or so while people snorkel over the corals or sunbathe on the boat, and there are frequently diving groups here too. There’s a 40,000đ charge to snorkel in this "protected area", though it’s not clear quite how it’s being protected.
After a break for lunch in the shelter of Hon Mot, boats head for Hon Tam, where there’s a small beach (10,000đ entry), and you get the chance to stretch on the sand or splash about in the sea for an hour before heading for the final destination, the Tri Nguyen Aquarium (25,000đ) on Hon Mieu. The setting here is wonderfully kitsch: visitors approach the site through giant lobsters and past cement sharks, and the strange building that houses the aquarium looks like a galleon dragged up from the depths and draped in seaweed. Inside, the tanks feature black-tipped sharks, bug-eyed groupers, hawksbill turtles and colourful sea anemones. Finally the boat heads back to the mainland and visitors are whisked back to their hotels.