Haizi Valley is the shortest and least demanding of the three valleys, starting from a trailhead about two kilometres from Rilong town and climbing through forested terrain to a series of glacial lakes. The full circuit takes three to four hours at a moderate pace, making it the practical choice for those arriving in the afternoon or for visitors who want a genuine hike without committing to a full day in Shuangqiao or Changping.
The valley sits east of the main town and faces the peaks that form the backdrop to Rilong. The lakes themselves — half a dozen varying in size from a few metres across to a proper alpine tarn — are clear at altitude and visually striking against the grey-brown rock. Wildlife sightings are more common here than in the busier valleys: the valley's smaller visitor numbers and its position on the eastern side of the watershed, which morning light crosses first, make early starts particularly worthwhile.