**The Côte-du-Sud riding features a tight three-way contest heading into the October 5, 2026 Quebec general election, with Valérie Hamel (PQ), Frédéric Poulin (PCQ), and incumbent Mathieu Rivest (CAQ) as the main contenders and Nancy St-Pierre (PLQ) trailing.** Recent candidate announcements through summer 2026 and early provincial polling have kept implied probabilities closely matched, reflecting a shift from the CAQ’s 2022 dominance. Projections from sources like Qc125 and Vote-Scope show the PQ, PCQ, and CAQ clustered in the mid-to-high 20s percent range, driven by broader provincial trends where the CAQ has lost ground while the PQ and PCQ gain in rural and agricultural areas. Local factors such as support for farming, regional health services, and economic development in the Bas-Saint-Laurent amplify the contest, as all three leading candidates emphasize ties to these issues. The early stage of the campaign—following the writ drop in late August—means limited separation so far, with traders viewing the outcome as sensitive to upcoming events like leader visits, candidate debates, and any new riding-specific polling. Late shifts in turnout or party momentum could still alter the balance before advance voting begins in late September.