The Son La Hydroelectric Reservoir is one of the largest artificial lakes in Vietnam, formed after the Son La Hydroelectric Power Plant officially began impounding water and operating. The reservoir stretches across the provinces of Dien Bien, Son La, and Lai Chau, with the section flowing through Muong Lay town (now Muong Lay ward, Dien Bien province) considered to have unique riverine landscapes and rich tourism potential.

Muong Lay ward is the confluence of the Da River, Nam Na River, and Nam Lay stream. When the hydroelectric reservoir was formed, the entire area became a vast expanse of water, with towering mountains reflected on the calm surface of the lake, creating a picturesque scene, often referred to as the "Ha Long Bay on land" of the Northwest region.

Beyond its significant importance in terms of energy and water regulation, the Son La Hydroelectric Reservoir also opens up opportunities for the development of ecotourism, waterway tourism, and cultural experience tourism. Visitors can participate in activities such as boat trips on the lake, admire the mountain and river scenery, visit lakeside villages, and learn about the daily life, customs, and traditions of the White Thai ethnic group – a long-standing community in Muong Lay.

Despite periods of impact from climate change and hydrology, the Son La Hydropower Reservoir is now basically stable, and its landscape is gradually being restored, creating favorable conditions for sustainable tourism development. With its harmonious blend of nature and local culture, the Son La Hydropower Reservoir is gradually becoming an attractive destination in the journey of exploring the Northwest region of Vietnam.