Rubber particles are incorporated in syntactic foams to fabricate hybrid syntactic foams having high failure strain and damage tolerance. Four different types of glass microballoons are used with two types of rubber particles resulting in eight different types of hybrid foam samples. These samples are tested for moisture and temperature effects at room temperature in salt water. ASTM D 5229-92 standard is used for hygrothermal testing. Instant oceanic synthetic sea salt is used to create salt water composition. Water absorption in all types of foam samples is measured until saturation. Compression testing is carried out as per the ASTM 365- 94 standard. The results obtained from hygrothermal and compression tests are compared with the previous results obtained from similar testing of plain syntactic foams. A comparison is also made with results from testing of similar hybrid foams subjected to moisture in deionized water. The compressive strength is compared with that of dry hybrid foam specimens.