The present study investigated the comprehension strategies that Taiwanese EFL high proficiency learners utilized when reading unknown language specific semantically incongruent and structurally congruent idiomatic language in four equally rich contextual environments. Specifically, the current study identified the idiom comprehension strategies employed for idioms without idiomatic equivalents in the participants’ L1. Data collection included individual interviews employing the think-aloud technique and semi-structured interviews. The relationships between strategy types, context types, and idiom types were explored. Participants employed four strategies when understanding semantically incongruent idioms and relied most heavily on guessing from context successfully using a variety of context clue types in successful meaning construction. Additionally, the results of a Welche’s T-test confirmed that semantically incongruent idiomatic expressions were more difficult for the participants to understand than structurally incongruent idioms. Pedagogical implications emphasized the importance of equally rich contextual environments and a strong working knowledge of idiom comprehension strategies for L2 users.