River climbing, river trekking, river tracing or mountain stream climbing is a form of hiking or outdoor adventure activity, a traditional sport in Japan and popular in Hong Kong and Taiwan, and, in some ways, similar to canyoning or canyoneering. River trekking is a combination of trekking and climbing and sometimes swimming along the river. It involves particular techniques like rock climbing, climbing on wet surfaces, understanding the geographical features of river and valleys, knotting, dealing with sudden bad weather and finding out possible exits from the river.

Out of the total 1,092 km2 of land in Hong Kong, three-quarters is countryside, with various landscapes including beaches, woodlands, and mountain ranges being found within the small territory. Most of Hong Kong's parks have abundant natural diversity, usually containing over 1,000 species of plants.