In response to a request from Saint Lucia’s Central Statistics Office (CSO), a technical assistance (TA) mission was conducted from September 2–13, 2024, to support the development of experimental expenditure-based GDP (GDP-E) estimates as a complementary product to the existing production-based GDP (GDP-P) program. The mission aimed to assess data sources and methods for all expenditure categories, produce experimental GDP-E estimates, identify data inconsistencies, and provide a roadmap toward publication. A product flow approach was introduced for household final consumption expenditure (HFCE) and gross fixed capital formation (GFCF), which incorporated domestic production, international trade, and estimates of intermediate consumption. Direct estimates were available for international trade in goods and services and government final consumption expenditure (GFCE). Experimental GDP-E estimates covering 2016–2023 were compiled using merchandise trade, balance of payments (BOP) statistics, benchmark supply and use tables (SUT), and domestic production statistics. While early-year results aligned well with GDP-P, the statistical discrepancy widened after 2018, notably during COVID-19. These gaps highlight potential data quality issues. The mission recommended; i) continuing GDP-E compilation to identify source data problems, ii) integrating GDP-E with the planned 2026 GDP rebasing exercise, and iii) expanding the SUT product dimension to improve HFCE and GFCF estimates.