Introduction: The purpose of this study was to examine the social and emotional loneliness of people (n = 216) over the age of 65 during the COVID-19 pandemic and then to understand in-depth the consequences of social isolation and loneliness among participants selected from the survey participants. Materials and Method: We used a sequential explanatory mixed methods design consisting of two phases. In the quantitative phase, the 11-item Loneliness Scale for the Elderly (LSE) was used for determining the level of loneliness. This scale was adapted by Akgul and Yesilyaprak (2015). In the qualitative phase, an open-ended question survey and semi-structured in-depth interviews were conducted with 14 participants chosen through purposeful sampling. Results: The quantitative data showed that the mean score for emotional loneliness (5.74) was higher than the mean score for social loneliness (2.14). There were no significant differences among the age groups. However, the mean score for overall loneliness increased (6.52) with age. There was a significant difference between overall loneliness and marital status (p = 0.025) and living alone (p = 0.046). Three major themes were identified in the qualitative phase: Emotional consequences, social consequences, and physical consequences. Conclusion: The results suggest that emotional loneliness and limited interaction with loved ones are the main consequences of the social isolation imposed during the pandemic. These results should be taken into account when developing strategies to facilitate the daily routines, well-being, social interaction-based activities, and social support systems for older people during times of social isolation.