The objective of this research is to measure the perception that teachers had about their own performance when they were forced to carry out Emergency Remote Teaching due to the COVID-19 pandemic. A questionnaire was provided to teachers of every educational stage in the Basque Country (Pre-school, Primary and Secondary Education, Professional Training, and Higher Education) obtaining a total of 4586 responses. The statistical analysis of the data shows that the greatest difficulties reported by educators are shortcomings in their training in digital skills, which has made them perceive a higher workload during the lockdown along with negative emotions. Another finding is the existing digital divide between teachers based on their gender, age, and type of school. A further worrying result is the lower technological competence at lower educational levels, which are the most vulnerable in remote teaching. These results invite us to reflect on the measures to be taken to improve equity, social justice, and the resilience of the educational system, which align with some of the Sustainable Development Goals.