Two species of vestimentiferan tubeworms (Escarpia sp. and Lamellibrachia sp.2) were reported at an area of low-temperature hydrothermal diffuse vent flow at the Mid-Cayman Rise (MCR) in the Caribbean Sea. We used a cultivation-independent metagenomic approach to characterize chemosynthetic symbionts in the trophosome tissue of Escarpia and Lamellibrachia at the MCR.