Intercultural communicative competence (ICC) has recently attracted the researchers' attention in the English as a foreign language (EFL) context; however, insufficient studies seem to have examined the role of online programmes in enhancing EFL learners' ICC. The current study, therefore, employed a mixed-methods approach to explore EFL learners' intercultural communicative effectiveness (ICE), a subcomponent of ICC, through telecollaborative language learning. Two intact classes, studying at a language institute, were selected as the participants of the study and were randomly assigned to an experimental group (henceforth referred to as the telecollaborative group) with 22 learners and a control group (henceforth referred to as the face-to-face group) with 20 learners. The learners in the telecollaborative group communicated with both native and non-native speakers of English by the means of online a/synchronous communication via Tandem, a language learning application, whilst the learners in the face-to-face group were taught intercultural issues during class time. The required quantitative and qualitative data were collected through an intercultural communication effectiveness scale and an individual semi-structured interview. One-way ANCOVA, applied to analyse the quantitative data, demonstrated that the EFL learners' ICE and its six subscales of behavioural flexibility, interaction relaxation, interactant respect, message skills, identity maintenance, and interaction management were developed in both groups after sharing intercultural background with foreign speakers of English worldwide and with their classmates during class time. Thematic analysis, utilised to analyse the qualitative data, uncovered some themes and categories indicating the learners' positive attitudes and perceptions towards the telecollaborative language learning activities. Practical implications are discussed next.