Microcoiled Si3N4 fibers have been prepared by the metal impurity activated chemical vapor deposition process using SiO-NH3-H-2-Ar gas mixtures. Growth conditions, microstructures, and mechanical properties of the Si3N4 coils were examined. Among the metal impurities used, Fe and Co were the most effective for growing coiled Si3N4 fibers. The coiled Si3N4 fibers were in amorphous state. The driving force of coiling or what affects the amorphous state during coiling is still unknown. The Si3N4 coils showed a maximum shear stress of about 12 GPa and the shear modulus of 110 GPa.