Differential Hippo-LATS-YAP signalling controls the first mammalian cell-fate decision, yet how human trophectoderm specification progresses to chorion formation remains unknown. Here we establish a developmentally informed model in which LATS kinase inhibition initiates the trophectoderm trajectory without exogenous morphogens. Stage matching to an integrated embryo-chorion single-cell reference revealed ordered progression from early trophectoderm to secondary chorionic lineages. Whole-genome bisulfite sequencing showed a naive-like hypomethylated state followed by remethylation, with key known placenta-associated imprinted domains retaining methylation and allelic bias. We then established a three-dimensional human chorion model by agitating induced-cell aggregates in suspension, yielding secondary chorionic lineages that self-organized with outward-facing trophoblast polarity and inside-out stromal-epithelial topology. Endogenous WNT signalling was dispensable for initial trophectoderm induction but regulated later chorionic lineage balance. Isolating CLDN6+ITGA6- cells identified a proEVT-like intermediate with villous and extravillous potential. Together, this framework connects human trophectoderm induction to three-dimensional chorion modelling and enables investigation of placental specification.