Total syntheses of the proposed and correct structures of iriomoteolide‐2a, a cytotoxic marine macrolide natural product with an unusual 23‐membered macrolactone skeleton, have been accomplished for the first time. The synthesis of the correct structure involves an asymmetric epoxidation/diepoxide cyclization cascade for the construction of the bis(tetrahydrofuran) moiety, a Suzuki–Miyaura coupling for the fragment assembly, and a ring‐closing metathesis for the closure of the macrocyclic backbone. In addition, the original stereochemical assignment of iriomoteolide‐2a was revised.