Climate change is affecting agricultural production in the coastal areas of the Mekong Delta through the intrusion of salinity into the rice (Oryza spp.) fields, where farmers cultivate photoperiod-sensitive rice varieties with long growth duration and low grain yields. A set of 12 stable crop wild relative (CWR)-derived rice lines with introgressions from wild rice Oryza rufipogon Griffiths and O. nivara S.D. Sharma & Shastry was evaluated for their phenotypic response to salinity tolerance by a participatory selection approach on farm in the Phuoc Long and Gia Rai districts, Bac Lieu province. The evaluation of the results showed that four lines derived from CWR are well adapted to the local environmental conditions, with high grain yield (>6.5 t ha−1), early maturity, and short plant height. These CWR-derived lines were adopted by farmers and proposed for testing on a larger scale in different areas of the coastal zone.