Although vaccines are recognized as one of the most successful public health measures, some individuals consider vaccination unsafe, ineffective, and unnecessary. The study aimed to evaluate knowledge and attitude of COVID-19 vaccines among pilgrims at a Hajj event (pilgrimage). A survey was conducted to assess knowledge and attitude toward COVID-19 vaccines among 251 pilgrims in Makkah City, Saudi Arabia. The results showed a moderate level of knowledge, with a mean of 76.1%. The majority (94.8%) of the participants know that “the COVID-19 vaccines are effective” followed by their knowledge “about the purpose of the vaccine” (84.5%). There was poor knowledge regarding the different types of COVID-19 vaccines (66.1%) and how they should be stored (66.1%). There was a strong agreement about the effectiveness of COVID-19 vaccines and to be taken during pilgrimage with a mean value of 4.4382 and 4.2311 respectively. Most pilgrims (46.6%) get awareness about COVID-19 vaccines from the official media, and social media (29.0%). There was a significant association between gender and the type of vaccines (P < 0.05). The Pfizer BioNTech vaccine was the most common vaccine used during the Hajj event (50.4%), followed by AstraZeneca (29.0%), Johnson & Johnson (24.7%), and Moderna (23.1%). It was concluded that there was a moderate level of knowledge and positive attitude regarding COVID-19 vaccines. Also, there was a strong agreement among pilgrims about the effectiveness of COVID-19 vaccines and the fact that they should be taken by all pilgrims.