The article introduces triangulation to converge evidence from corpus and experimental data, by means of two case studies in second language (L2) learners of Greek. The first case study investigates the acquisition of gender agreement, while the second probes the development of relative clauses. In both studies, findings from the corpus are tested against online experimentation using eye-tracking and self-paced reading tasks, a combination that is scarce in research implementing triangulation. The findings suggest that methodological convergence yields both congruous and incongruous evidence. However, both types of evidence contribute to a nuanced understanding of the linguistic phenomena under study, as well as the different perspectives from which they are approached. The article concludes that such an approach to triangulation can significantly contribute to enhancing the reliability and validity of the findings, provided that methodological convergence has been achieved at the design level of the study.