The climate and biodiversity crises reveal a failing human–nature relationship. The psychological construct of nature connectedness provides a means for understanding and improving that relationship. Furthermore, recent research suggests that higher levels of nature connectedness benefit both people and the environment, promoting pro-nature conservation actions, pro-environmental behaviors, and greater personal well-being. Nature connectedness is, therefore, emerging as a key target to improve human and nature's well-being. Using data from a large national survey in the United Kingdom, the present research investigates how nature contact and noticing nature activities predict nature connectedness. Multiple regression analyses revealed that noticing nature, through activities that involve active sensory engagement with wildlife, explained levels of nature connectedness over and above simply spending time in nature. Moreover, the activities engaged in when in nature had differential effects on nature connectedness. Watching, listening to, and photographing wildlife were significant predictors of nature connectedness, whereas studying nature, looking at scenery through windows, observing celestial phenomena, and collecting shells and rocks were not. The results have implications for how best to improve nature connectedness, both in terms of how to design and improve greenspaces, and in terms of how to better engage the public with nature for a healthy and sustainable future.