q of linear codes is said to be self-orthogonal if the duals of the codes in the flag satisfy C ⊥ i = C s−i , and it is said to satisfy the isometry-dual property with respect to an isometry vector x if C ⊥ i = xC s−i for i = 1, . . . , s. We characterize complete (i.e. s = n) flags with the isometry-dual property by means of the existence of a word with non-zero coordinates in a certain linear subspace of F n q . For flags of algebraic geometry (AG) codes we prove a so-called translation property of isometry-dual flags and give a construction of complete self-orthogonal flags, providing examples of self-orthogonal flags over some maximal function fields. At the end we characterize the divisors giving the isometry-dual property and the related isometry vectors showing that for each function field there is only a finite number of isometry vectors and that they are related by cyclic repetitions.