The use of mobile data is increasing during the pandemic COVID-19 due to social distancing. Many daily activities depend on internet activity. Mobile network operators as internet service providers are required to be able to meet increasingly high data needs by providing a reliable network. This research aimed to determine, analyze, and compare the efficiency of mobile network operators before and during the pandemic COVID-19 using Data Envelopment Analysis (DEA). The variables used to measure efficiency in this research were company operational variables. The input variable was the number of BTS, while the output variables include the number of subscribers and data traffic.The data used in this research came from company annual reports from 2015 to 2020. This result shows that during the COVID-19 pandemic, the average efficiency value achieved by mobile network operators was higher than the previous years. Correlations between each variable with efficiency on each company are different. Telkomsel efficiency is mostly affected by the number of BTS, Indosat Ooredoo efficiency is by the number of subscribers, and XL Axiata efficiency is by data traffic.