•SiCw-SiC foams with hollow skeleton were synthesized by chemical vapor infiltration of SiC film and SiC whiskers using flexible carbon foam as template.•The SiCw-SiC foams possess a large number of smaller pores due to the segmentation effect of the SiC whiskers.•SiCw-SiC foam exhibits an excellent thermal insulation property at high temperature.SiCw-SiC foams with hollow skeleton were synthesized by a simple procedure that consisted of the chemical vapor infiltration (CVI) and oxidation process. Flexible carbon foam was employed as CVI template. A typical structure of SiCw-SiC foams consisting of SiC supporter with hollow skeleton structure accompanying numerous crooked SiC whiskers was obtained after burning out carbon skeleton of the carbon foam during oxidation process. SiCw-SiC foams have a density of 0.11 ≤ ρ ≤ 0.12 g/cm3, porosity ≥ 96% and a thermal conductivity at room temperature between 0.040 and 0.075 W/m·K. Thermal conductivity of the SiCw-SiC foams moderately increased with elevation of temperature, indicating that these foams with larger amount of whiskers exhibit excellent thermal insulation property at elevated temperature.