Prepregs for producing ceramic-ceramic composite articles are prepared by impregnating a ceramic substrate with a liquid ceramic precursor material. By properly controlling the viscosity of the precursor material and the conditions of application of the precursor to the substrate, a prepreg which can retain the precursor may be obtained. The prepreg is suitable for shaping into a wide variety of geometries, and the ceramic precursor may be transformed into the corresponding ceramic matrix material by curing and conversion steps.