(1) The COVID-19 pandemic poses threats to human life and health around the world. This study attempts to determine the correlation between loneliness and satisfaction with life among nursing students in Poland, Spain and Slovakia and to seek predictors of social and emotional loneliness among the students. (2) A total of 756 nursing students from Poland, Spain and Slovakia took part in the study. A diagnostic survey was applied as the research method, and the data were collected with the sense of loneliness measurement scale (de Jong Gierveld Loneliness Scale–DJGLS) and the Satisfaction with Life Scale (SWLS). (3) The mean age of the participants was 21.20 years (SD = 1.97). A correlation analysis revealed statistically significant, negative correlations, with an average and high strength, between the general sense of loneliness and its components (social loneliness and emotional loneliness) and satisfaction with life among students in Poland, Spain and Slovakia. A regression analysis showed one’s satisfaction with life to be a predictor of a sense of loneliness among nursing students in Poland, Spain and Slovakia in the second year of the COVID-19 pandemic. (4) Students with a stronger sense of loneliness also feel lower life satisfaction. It is important to take preventive and prophylactic actions concerning loneliness among students during and after the COVID-19 pandemic.