Given \({{\mathbb {F}}}_q\) the finite field of size q, a flag code on \({{\mathbb {F}}}_q^n\) consists of a set of flags with a fixed sequence of dimensions (the type). In this paper, we deal with cyclic orbit flag codes, that are orbits of a Singer cycle of the general linear group acting on flags on \({{\mathbb {F}}}_q^n\) . Inspired by the results in Gluesing-Luerssen and Lehmann (Des Codes Crypt 89:447–470, 2021) and Roth et al. (IEEE Trans Inf Theory 64(6):4412–4422, 2018) about cyclic orbit codes, we completely characterize those cyclic orbit flag codes attaining the best distance for the largest possible orbit size, that is, optimal full-length cyclic orbit flag codes. Finally, we show that the distance distribution of this family of codes depends only on q, n and the type of the generating flag, also addressing the case of a union of orbits.
