Loneliness, as a well-established risk factor of mental health, has been strongly associated with low subjective well-being (SWB). However, less is known about potential boundary conditions that may ameliorate this ‘dark side’ of loneliness. Social connections are critical to well-being from the standpoint that the lack of belonging was detrimental to human survival in the evolutionary past. We thus hypothesized that loneliness would exert a more pronounced influence on people’s SWB when the need for others (social resource) is perceived to be high–the presence of environmental harshness. With a particular focus on urban (i.e., Seoul) residents who are presumed to be more vulnerable to loneliness, two studies examined whether feeling lonely matters less to SWB under favorable environmental conditions. As expected, loneliness was less harmful to the SWB of individuals who perceived their surroundings as relatively secure and favorable (Study 1). We then experimentally replicated the results by exposing people to cues of either a harsh (e.g., images of scarcity) or a favorable environment (Study 2).