We investigate the photoproduction of K Ã0 AE þ and K Ãþ AE 0 off the proton target, employing the effective Lagrangian approach at the tree-level Born approximation. In addition to the ðs; t; uÞ-channel Born diagrams, we take into account various baryon-resonance contributions such as D 13 ð2080Þ, S 11 ð2090Þ, G 17 ð2190Þ, D 15 ð2200Þ, S 31 ð2150Þ, G 37 ð2200Þ, F 37 ð2390Þ, and AE Ã ð1385; 3=2 þ Þ in a fully covariant manner. We present the numerical results for the energy and angular dependences for the cross sections in comparison to available experimental data. The single-polarization observables, i.e., the photon-beam (AE ), recoil (P y ), and target (T y ) baryon polarization asymmetries are computed as well for future experiments. We observe from the numerical results that the resonance contributions play a minor role in producing the strength of the cross sections, being different from the K Ã Ã photoproduction. In contrast, it turns out that the Áð1232Þ-pole contribution and K exchange in the t channel dominate the scattering process. On the other hand, the higher resonances influence the polarization observables such as the recoil and target asymmetries.