This article examines the role, meaning, and practice of letter writing in the lives of two Finnish girls during the Second World War (WWII). We use a particular set of letters (N = 41) from the wartime letter collection kept in the Tampere University Folklife Archives and argue that they give us an interesting perspective on not only the girls' wartime experiences, but also on the role of communication and pen-pal writing in everyday life. In particular, we focus on one evacuee -- Ritva -- who during the period 1939-1945 changed class six times, requiring her to constantly adapt to new class environments and peer relationships. However, from 1942 onwards, the correspondence with her pen pal Ella provided Ritva with a sense of continuous friendship free from the pressures of local peers. We suggest that pen-pal writing formed an arena of communication which allowed the two girls to share experiences, nurture mutual feelings, and give each other support -- elements which might have sometimes been lacking in relationships they had locally with adults and peers at this time. In theoretical terms, this article is inspired by approaches from the history of experiences and history of emotions. These provide useful concepts for pinpointing the historical and cultural layers involved in the social process of cultivating a pen-pal correspondence.