The family Cryptacanthodidae comprises 4 species: 3 in the North Pacific Ocean and 1 in the western North Atlantic Ocean. Two species in particular, Cryptacanthodes aleutensis and C. giganteus, occur sympatrically in the eastern North Pacific from the Bering Sea to off the coast of northern California. Both species have neustonic larvae with elongate bodies and heavy pigmentation. Descriptions and illustrations of larvae for both species are provided. Meristic and pigmentation characters can be used to distinguish between the species, with C. giganteus having higher total vertebral and dorsal-fin spine counts and less overall pigmentation than C. aleutensis. Comparisons are also provided to distinguish both species from other elongate, heavily pigmented neustonic larvae that co-occur in the eastern North Pacific Ocean. In general, cryptacanthodids can be distinguished from other neustonic larvae because they have a higher total vertebral count, a long dorsal fin composed solely of spines, and an absence of pelvic fins.