The article presents a study of five Polish multicultural and multilingual families in Finland, and their engagement in digitally mediated family communication. Explored through an ethnographic inquiry into the in-app communication practices of Polish migrant mothers and children, the study contributes to the body of research at the intersection of new media and communication, transnational family and migration studies, and family multilingualism. Building on the concept of virtual proximity, which refers to the emotional closeness between individuals afforded by digital technologies and mobile communication, the study identifies four thematic patterns in participants' practices in digital habitats: (i) children's agency in creating family WhatsApp groups, (ii) the use of family in-app communication for language learning purposes, (iii) digital caregiving strategies and arrangements, and (iv) the use of digital photo-sharing as a form of visual co-presence. Children's and mothers' practices in digitally mediated communication differ from each other, but they lead to the formation of transnational familyhood in digital habitats. In this context, achieving virtual proximity by digital means helps to fulfil aspirations to remain a family across distance.