This study examined how three task activities with receptive (R) reading, cloze (CZ) and receptive-productive (RP) integration differently lead to L2 idiom recall and retention by Korean EFL adult learners when they are enhanced with bolding, L1 glossing and three repetitions. It further looks into what features of the enhanced input tasks influence L2 idiom gains. The theories of input enhancement, receptive and productive task input are the basis for the present study. The results revealed that overall the three tasks contributed to high score of L2 idiom gains in immediate receptive, productive recall and delayed receptive retention, except delayed productive retention. There was no significant difference in idiom recall and retention by the three tasks. The descriptive analysis showed R group performed better on immediate receptive recall, while CZ group led the highest score of immediate productive recall. In terms of retention gap between immediate and delayed tests, the three tasks yielded high percentage of receptive idiom retention. The CZ task yielded the highest percentage of receptive retention but relatively low percentage of productive retention, while the R group retained most memory of productive knowledge. The results suggest some implications for effective L2 idiom teaching materials using input enhanced tasks such as bolding, L1 glossing and repetition.