This study investigates grandparent–grandchild relations in emerging adulthood, focusing on grandchildren’s transition to residential independence and the role of parents as mediators. Using three waves of the German Ageing Survey (DEAS), we estimate fixed effects models to assess changes in the frequency of contact and emotional closeness of 349 grandparents with 494 grandchildren aged 16 to 30 years. Grandparent–grandchild contact decreases during the transition to adulthood due to the middle generation’s declining ability to provide opportunities for intergenerational interaction as well as grandchildren’s new responsibilities after leaving the parental home. Grandparent–grandchild closeness does not change systematically in emerging adulthood, but is characterized by a high degree of temporal stability and independence of grandparent–parent contact frequency. Thus, even if contact decreases during the transition to adulthood, a continuously close emotional bond allows grandparents and grandchildren to (re)activate the support potential inherent to their relationship in times of need.