Modern childhood is increasingly segregated from nature. Yet, children’s nature experiences are first steps for sustainable futures. In this thesis, I research the foundations of habitats that can connect children to nature. I call them nature-connecting habitats. Five papers in this thesis answer: (RQ1) what is children’s human-nature connection (HNC)?; and (RQ2) what are the requirements of nature-connecting habitats for children? The preschools paper shows that five-year-olds with nature-rich routines have higher HNC than children with nature-poor routines, but it cannot understand which nature experiences are most influential. Hence, the salamanders paper assesses children’s participation in a nature conservation project. Discrepancies between the qualitative and quantitative results reveal an assessment gap with theoretical roots, which impedes the assessment of nature experiences in practical time-frames. To close this gap, the review paper surveys the literature and shows that attributes of the mind, qualities of nature experiences, and attachment to places are all aspects of HNC. The embody paper conceptualizes an embodied approach to HNC to overcome the barriers identified previously, and the toolbox paper operationalises it to develop a toolbox to assess children’s HNC and nature-connecting habitats. Answering RQ1, results show that children’s HNC is a complex set of embodied abilities. Human-nature relationships that could enable, promote, or assist sustainable development are a set of abilities that children can learn. These abilities are relationships between mind, body, culture, and environment, and progress following non-linear dynamics. This thesis identifies 10 of these abilities of HNC and finds that children learn them in three consecutive phases. Phase one – being in nature – includes feeling comfortable in natural spaces, and being curious about nature. Phase two – being with nature – includes reading natural spaces, acting in natural spaces, feeling attached to natural spaces, knowing about nature, and recalling memories with nature. Phase three – being for nature – includes taking care of nature, caring about nature, and being one with nature. Answering RQ2, two requirements of nature-connecting habitats are found: significant nature situations and various nature routines. Nature situations that can connect children to nature are characterised by configurations of 16 qualities – qualities of significant nature situations. These qualities are: entertainment, thought-provocation, awe, surprise, intimacy, mindfulness, self-restoration, creative expression, physical activity, challenge, engagement of senses, child-driven, involvement of mentors, structure/instructions, social/cultural endorsement, and involvement of animals. This set of qualities delineates the kinds of nature situations that nature-connecting habitats have to provide. These qualities should be various and recurring to allow children’s HNC to progress – hence, various nature routines. These lists of abilities and qualities form a toolbox capable of assessing where and how children connect to nature, named ACHUNAS. This thesis sets the stage to develop nature-connecting habitats. Children’s HNC and nature-connecting habitats are not the only intervention to promote sustainable futures, but they might be necessary conditions to meet the ever-shifting target of sustainable civilizations.