Using unique Italian survey data on both documented and undocumented immigrants, we empirically quantify the correlation between different types of personal contacts and immigrants' documentation probability, while also uncovering the contacts' indirect associations via immigrant labour market outcomes (employment status and job characteristics). Our results indicate that contacts with both natives and family members have a positive and quantitatively large effect on immigrant documentation probability, conditional on a large set of covariates. Contacts with members of the same ethnic group, by contrast, increase documentation probability only moderately, an effect explainable by these co-ethnics' association with employment probability. Moreover, our findings support the hypothesis that native contacts can connect immigrants with jobs that favour documentation.