The decarbonisation of short-sea and inland waterway transport is one of the most operationally complex challenges in maritime climate policy, owing to fleet size, route diversity, and the limited applicability of fuel-switching technologies at the cargo scale. This study provides independent technical and environmental validation of the COSCO SHIPPING Zhong Yuan Hai Yun Lü Shui 01 and 02—the world's first 10,000 DWT pure-electric river–sea container ships, which entered commercial service on the Nanjing–Yangshan (Shanghai) corridor on 22 April 2024. Technical parameters were triangulated from five categories of primary source; CO2 reductions were quantified using IMO Tier III emission factors; and the analysis was extended to well-to-wake upstream emissions and a battery lifecycle assessment drawing on peer-reviewed LCA literature. Each vessel integrates a fixed 50.4 MWh lithium iron phosphate (LFP) bank with 24 operational swappable 1.6 MWh ISO containers (38.4 MWh), enabling a 540 NM range at 10.5 knots while preserving the full 700 TEU payload. Tank-to-wake CO2 avoided was confirmed at 12.3 t per 100 NM; annual reductions range from 2,918 t (42% utilisation) to 6,922 t at full utilisation, equivalent to 2,032–4,820 passenger cars. Well-to-wake analysis incorporating China's 2024 grid intensity (560 gCO2/kWh) yields a net advantage of 6.1 t CO2 per 100 NM, rising to 7.1 t/100 NM under H1 2025 intensity (492 gCO2/kWh), suggesting decarbonisation is proceeding faster than projected. LFP manufacturing carbon debt at median LCA intensity (62 kgCO2/kWh) is 2,381 t for the operational swappable system, giving a carbon payback period of under one year. Annual fuel savings are confirmed at $738,400–$1.75 million at $800/t MDO. These results demonstrate that battery-electric propulsion is a technically and economically viable pathway for decarbonising heavy cargo operations on major inland waterway corridors. Scalability is contingent on interoperability standards for battery-swapping infrastructure and continued decarbonisation of the charging grid.