Pui O Beach runs along almost the entire shoreline of Pui O village, 260 metres of coast framed by the Chi Ma Wan Peninsula to one side and the lower slopes of Sunset Peak to the other. The beach's water supply comes from two sources simultaneously: the open sea, and the river system that drains a valley to the east, gathering in an estuary of wetland before reaching the shore. This confluence of fresh and salt water is not accidental — it is geography. The wetland that forms where the rivers slow was, for centuries, converted into rice paddies by Pui O villagers, who understood that the soil enriched by tidal flooding was fertile. The beach itself is the terminal feature of this whole landscape: the point where everything — hillside, valley, river, sea — arrives at once.

Pick up a handful of sand at Pui O and you will see what the geology is doing. Yellow grains, the product of quartz-bearing rock worn from the surrounding hills. Black grains, from darker volcanic rock that also outcrops in this part of Lantau. The mixture is not uniform — at different points on the beach, in different seasons, one colour can dominate. After storms or heavy river flows, the composition shifts. It is one of those details that rewards attention: most beach visitors do not look at sand closely enough to notice what it is made of, but Pui O's unusual mix tends to catch the eye. The government's Environmental Protection Department has rated the beach's water quality as good to fair over the past two decades — a reasonable result for a beach at a river junction, where the freshwater inflow can carry runoff from the catchment.

Pui O sits at the boundary of Lantau South Country Park, and the beach reflects that adjacency. The upper beach has camping facilities — constructed and managed by the Hong Kong government — that make Pui O one of the more accessible wild camping destinations within the city. Families arrive with tents and barbecue equipment, setting up in a landscape that is simultaneously managed park and working coastline. Wooden fences divide the camp bays; the ground is mostly sand. Restaurants line the road behind the beach, selling food and swimming supplies. The combination of facilities and relative remoteness — Pui O is on the South Lantau Road, reachable by bus from Mui Wo, but not a short journey from urban Hong Kong — creates a particular atmosphere, simultaneously relaxed and slightly away from things.

Because Pui O Beach faces south-southwest, it catches the late afternoon sun in a way that north- or east-facing beaches cannot. The sun descends toward the South China Sea, and the beach is positioned to watch the whole arc of it. This is a geography-determined pleasure: the orientation that the Chi Ma Wan Peninsula and the hillsides impose on this particular bay happens to align with the direction of the evening sky. Visitors who arrive in the late afternoon for this specific purpose — and many do — tend to time their arrival to the hour before sunset, when the light on the water flattens and then turns gold. The black-and-yellow sand takes on additional complexity at that light level. It is a small thing, directional orientation, until you are sitting on the right beach at the right time facing the right direction.

On 23 November 2018, a bull named Billy died on the beach at Pui O. He was eight years old, widely known among regular visitors to the area — water buffalo roam freely in Pui O, one of the few remaining places in Hong Kong where they still do, descendants of animals once used for farming that have since gone feral. Billy's death was not from natural causes. An examination found that his stomach and intestinal tract were blocked with plastic bags, enough to fill two rubbish bins. He had eaten what people had left. His death was reported widely and prompted calls for beachgoers to take their rubbish with them when they leave. The water buffalo are a living piece of Pui O's agricultural past; they have outlasted the rice paddies and the farming economy. Billy had lived on that beach his whole life.