Most research studies show the focus of EFL courses in the Iranian educational context is on speaking in private language schools and on grammar, reading and vocabulary in state schools. Consequently, more research regarding writing is required in the Iranian EFL context. The present study sets out to investigate the effects of input enhancement and input flooding of the present simple and continuous tenses on Iranian EFL learners' writing. Moreover, the study examined learners' perceptions of the efficacy of the two input types for improving writing. The participants were 60 EFL learners in three groups of 20. In experimental group one, present simple and continuous tenses in texts were enhanced via underlining, boldfacing, italicization, capitalization, colour coding and using different font sizes. In experimental group two, learners received flooded materials via increasing the frequency of tenses. The control group was exposed to the same texts; however, the texts were neither enhanced nor flooded. After the treatment, the three groups received the writing posttest. To explore learners' perceptions towards the efficacy of input types for improving their writing, five participants in each experimental group were interviewed. The results indicated that both input enhancement and input flooding positively affected learners' writing.