Things to Do in Halong in May

This full-day cruise threads through the densest karst field in the bay, where limestone towers rise sheer from water so still it mirrors them well in the early morning before the breeze picks up. The onboard buffet leans heavily on regional seafood, grilled tiger prawns, steamed morning glory with garlic, and a tangy tamarind soup loaded with clams, served on an upper sun deck where the salt wind carries traces of charcoal smoke from the galley below. After lunch, kayaks launch directly from the stern platform into shallow lagoons ringed by overhanging rock, and the swimming stop drops you into warm, opaque-green water beside a karst wall streaked orange with iron oxide.

The roughly four-hour drive southeast from Hanoi crosses the flat Red River Delta before the landscape crumples into the karst hills that signal the bay's approach, and the transfer itself is part of the experience, rice paddies electric green from spring planting, brick kilns sending thin columns of smoke into humid air, and roadside stalls selling still-warm bánh cuốn wrapped in banana leaf. Once aboard, the cruise traces a route through Halong's inner islands with stops at a stalactite cave whose formations glow amber and pink under carefully placed spotlights, the cool interior a sharp relief from the heat outside. Lunch is a sit-down spread anchored by local crab steamed with lemongrass, its shell cracking easily under the provided mallet, the flesh briny and sweet.

This cruise distinguishes itself with a longer kayaking segment that pushes past the usual lagoon loop and into narrower channels where the karst walls close in overhead and the water turns almost black beneath the shadow. The silence inside these corridors is startling, engine noise vanishes, replaced by the drip of water off stalactites and the hollow knock of your paddle against the hull. Back on board, the buffet lunch includes a carving station with slow-roasted pork belly glazed in fish sauce and palm sugar, its skin lacquered and crackling, alongside platters of cold rice-paper rolls stuffed with herbs so aromatic you smell the Thai basil and perilla before you pick one up.

Catherine Horizon runs a newer steel-hulled vessel with a rooftop lounge finished in teak and brass, and the dinner service is the centrepiece: a multi-course Vietnamese-French menu served as the sun drops behind the karst silhouettes and the deck lights come on, casting warm pools across white linen. Expect dishes like seared Halong Bay squid on a bed of green mango salad dressed with nuoc cham, followed by slow-braised beef cheek with star anise and cinnamon bark, the sauce reduced to a glossy, savoury concentrate. The vessel anchors in a quieter arm of the bay for the meal, and after plates are cleared you can stand at the bow rail and watch the squid boats' green lamps switch on one by one across the dark water, the smell of the sea mixing with the lingering warmth of charcoal from the galley.

This three-day retreat splits between Yen Tu Mountain, the spiritual heart of Vietnamese Zen Buddhism, and a quieter stretch of the Halong Bay coastline. The Yen Tu segment involves a dawn climb through cloud forest where the trail passes pagodas dating to the Tran Dynasty, their stone steps worn smooth by centuries of pilgrims, the air dense with the scent of damp earth and incense drifting from altars tucked into rock niches. Meditation sessions happen in open-air pavilions partway up the mountain, and in the early morning the fog sits so thick you can feel it bead on your forearms. The Halong portion brings the practice to the water, with guided sitting meditation on the deck of a small boat as the karsts materialise slowly out of morning mist like ink-wash paintings gaining definition.

A half-day loop that departs directly from Halong City's port rather than requiring the drive from Hanoi, this four-hour circuit is built for travellers already based on the bay. The boat enters two caves in quick succession, the first a cathedral-scaled grotto where stalactites hang close enough to graze with outstretched fingers and the cool air inside smells faintly of wet calcium, the second a tighter passage where the guide's torch picks out formations shaped like animals and rice terraces, their surfaces glistening with condensation. Between caves, a short kayak segment takes you along the base of a karst wall where ferns and small fig trees grip the rock, their roots dangling into the water like frayed rope.