Two new species, one in the genus Incendia, and one in Seiria, are illustrated and described here from mesophotic peyssonnelioid specimens collected in the Hawaiian Islands based on molecular and morphological analyses. Both genera are reported from Hawai‘i for the first time. Incendia lisianskiensis sp. nov. differs from the other nine described members of the genus by its lack of hair cells, by the perithallial filaments arising at a more or less 90º angle from the hypothallus, while Seiria mesophotica sp. nov. is distinguished from the only other described species, S. magnifusa, by its lack of obvious and well-developed perithallial cell fusions. With the description of these two species the total number of recognized Hawaiian members of the Peyssonneliales rises to nine. Previously recorded species included Peyssonnelia conchicola, P. inamoena, P. japonica, P. rubra, Ramicrusta hawaiiensis, R. lehuensis, and Sonderophycus copusii.