We investigated power splitters in air core waveguides with a metallic photonic crystal cladding. The mechanism of propagation in these guides is the total external reflection. The cladding is formed by a periodic arrangement of metallic wires on square or triangular lattices. Power splitters can be designed by modifying the geometry at the splitting region by introducing a reflecting structure in order to increase the transmission coefficient. Some splitters based on these structures are analyzed by an efficient frequency domain finite element approach. © 2005 IEEE.