| Navicula cari var. angusta (Grunow) Grunow, 1885 |
| Navicula cari var. cari Ehrenb., 1836 |
| Navicula cari var. recens Lange-Bert., 1980 |
| Navicula caribaea Cleve, 1874 |
| Navicula carinifera Grunow, 1874 |
| Navicula charlatii M. Perag., 1921 |
| Navicula cincta (Ehrenb.) Ralfs, 1861 |
| Navicula cincta var. cari (Ehrenb.) Cleve, 1895 |
| Navicula cincta var. cincta (Ehrenb.) Ralfs, 1861 |
| Navicula cincta var. heufleri (Grunow) Van Heurck, 1885 |
| Navicula circumtexta Meister & Hust., 1934 |
| Navicula clamans Hust., 1939 |
| Navicula clavata W. Greg., 1856 |
| Navicula clementis Grunow, 1882 |
| Navicula coarctata A. Schmidt, 1875 |
| Navicula cocconeiformis Greg. ex Grev., 1855 |
| Navicula confecta A. Schmidt, 1875 |
| Navicula confervacea (Kütz.) Grunow, 1880 |
| Navicula confervacea var. confervacea (Kütz.) Grunow, 1880 |
| Navicula contenta Grunow, 1885 |