Online learning has become a highly effective tool for many language learning institutions and educational environments. However, very limited attention has been directed towards the teacher element in online learning environments in ESP/EAP instruction. To fill this gap, this study investigated the attitudes of 91 Iranian EAP instructors towards the implementation of online EAP instruction. A mixed-methods design was employed in this study, with both semi-structured interviews and questionnaires used to examine the participants' perspectives. The findings of the study revealed that the majority of the participants hold positive attitudes towards the implementation of online EAP instruction while they are fully aware of the challenges and obstacles to the implementation of online EAP instruction in the Iranian context. Several limitations, including the lack of online EAP teacher training, the lack of facilities for online learning implementation, low digital literacy levels of instructors and students, and the lack of online instruction infrastructures were identified and reported. The participants also pointed out several practical measures and suggestions in order to pave the way for incorporating online EAP instruction which can be considered by EAP policy-makers and course designers. The study can have practical and theoretical implications for the renewal of EAP instruction in Iran and in other countries.