This study presents a corpus-based investigation of self-repairs in hearing adult L2 (M2L2, second modality and second language) learners of Swedish Sign Language ("Svenskt teckenspråk," STS). This study analyses M2L2 learners' STS conversations with a deaf signer and examines the learners' self-repair practices and whether there are differences among learners of different proficiency levels. This provides a description of characteristics of self-repair made by M2L2 learners as well as the frequency and distribution of self-repair categories. The results show that the frequency of self-repair decreases with increased proficiency, at least after the initial stage. Furthermore, the self-initiated repair categories of the beginners are often phonological repairs, while intermediate learners tend to carry out self-repairs at the lexical and syntactic level. The results also reveal a specific type of STS repair linked to fingerspelling repairs. We discuss the effects of second modality learning as well as the relationship between monitoring and language proficiency.