This report synthesises evidence on the effects of the availability of legal pathways on irregular migration. Regular migration pathways include labour mobility regimes, sponsorship programmes for high skilled workers, student visas and protection for refugees. In contrast, irregular migration pathways include illegal entry, overstaying a visa and befallen irregularity (where regular status is lost). The links between regular (legal) pathways for migration and irregular migration are complex, however, two linked assumptions are common in the evidence base for this report. The first assumption is that destination states’ restrictive migration policies and the lack of regular pathways pushes migrants into irregular entry, illegal residence and befallen irregularity. The second assumption is that expanding regular migration will reduce irregular migration as people would chose to migrate regularly if options were available. Options for expanding regular pathways include labour mobility regimes, safe pathways for refugees and expanding visa options for students and low-skilled workers. However, it is also possible that expanding regular pathways could result in increases in irregular migration and smuggling along specific corridors.