There are two types of cilia, primary cilia and undulipodia, which are distinguished by differences in the structure of their axoneme. The level of calcium ions (Ca2+) inside the cilia is regulated by specialized ion channels. (A) The main Ca2+ channel for primary cilia has been identified as the PKD1L1/PKD2L1 complex. (B) There are two types of undulipodia: motile cilia and flagella. The main Ca2+ channel of mammalian flagella was identified as a protein called CatSper in 2013. Doerner et al. have now identified an L-type voltage-gated Ca2+ channel (Cav1 family) as the main Ca2+ channel for motile cilia.