Global efforts toward decarbonisation and the phase-out of nuclear power have driven a rapid worldwide expansion of solar photovoltaic (PV) infrastructure. While rooftop systems impose limited ecological risks, large-scale ground-mounted PV installations are increasingly being developed on farmlands, wetlands, and coastal zones, posing new conservation challenges. Such installations may fragment habitats, alter hydrological systems, and disturb wildlife, yet their impacts on migratory shorebirds remain poorly quantified along the East Asian–Australasian Flyway (EAAF)—the world’s most threatened migratory corridor. This study assessed the associations between solar PV expansion and wintering shorebird diversity along the Changhua coast in western Taiwan, a key EAAF stopover containing extensive tidal flats, three Important Bird Areas (IBAs), and a national protected area. Between October 2024 and March 2025, 48 eBird checklists recorded 2,987 individuals of 70 species, complemented by population trend data from the Taiwan New Year Bird Count (2014–2022). The results showed significant growth in Little Ringed Plover (Charadrius dubius), while Sanderling (Calidris alba) and Wood Sandpiper (Tringa glareola) exhibited significant declines. Generalised linear mixed models indicated that higher PV coverage was significantly and negatively associated with shorebird species richness, suggesting possible habitat displacement or disturbance where solar arrays overlap with intertidal wetlands. These findings highlight the urgent need for evidence-based spatial planning and adaptive management to balance renewable energy expansion and biodiversity conservation. We recommend prioritising PV development on rooftops, brownfields, and abandoned salt pans retaining wetland functions, while avoiding tidal flats, active wetlands, and key foraging or roosting sites. Establishing ecological buffers, regulating construction seasons, and conducting pre- and post-construction monitoring through citizen-science platforms such as eBird and the NYBC would enhance accountability and transparency. Moreover, cumulative-impact assessment and data-sharing mechanisms within EAAF frameworks are essential for mitigating transboundary risks. This study demonstrates that renewable energy development and migratory bird conservation are not conflicting goals, but achieving both requires coordinated regional governance, continuous monitoring, and scientifically informed siting strategies.