Despite the known benefits of precision agriculture, the adoption is challenging due to the cost of investment and the farm sizes. Therefore, profitability is an important aspect to consider. This study aimed to evaluate the net returns, profitability, and investment efficiencies of PA by different economic farm sizes. The study was based on data retrieved from the Farm Accountancy Data Network (FADN) and Eurostat (year 2021). The study examined four countries (Poland, Germany, France, and Romania) under field crop farming using an investment cost of EUR 35,941–EUR 71,883 and a 20% and 15% reduction in the cost of crop protection and fertilizer usage, respectively, without compromising productivity. There is a positive relationship between the adoption of PA and farm returns for larger-scale farms. The result of the profitability and analysis of investment efficiency using Net Present Value (NPV) showed a positive value for economic farm sizes of EUR 100,000 and above. Hence, it is not economically advisable that all farmers use PA technologies with the hope that they will be profitable but with public support (subsidies) more farms will be able to use PA and be profitable. This is also an opportunity to meet the goals of the European Union Green Deal of minimizing emissions that cause climate change.