A novel coronavirus, formerly called SARS-CoV-2 by the International Committee on Taxonomy of Viruses, caused an outbreak of atypical pneumonia in Wuhan, Hubei province by December of 2019 and then rapidly spread out in the whole China. In March 2020, the SARS-CoV-2 spread to Venezuela and Ecuador. The basic reproduction number (R0 ) is a value that allows measuring the transmission rate of a virus. The SIR model is the simplest compartmental epidemiological model (Susceptible, Infectious, and Recovered). The SIR model can be used to estimate R0 by fitting the curve of the infected compartment to the experimental curve of infected subjects per day. This work aims to study the projection of the R0 of SARS-CoV-2 in Venezuela and Ecuador. For this purpose, five experiments took place by adjusting the SIR model curve of the infected compartment to experimental data at five-time intervals (the first 14, 28, 42, 56, and 178 days for Ecuador data and 165 days for Venezuela data). The R0 fell from 6.923 to 1.003 (between experiments 2 and 3) for Venezuelan data, and from 3.622 to 1.022 (between experiments 1 and 2) for Ecuadorian data. These differences imply that R0 depends on the preventive measures implemented to face the pandemic. On the other hand, the number of infections in Ecuador is higher compared to the infection numbers in Venezuela in each experiment. Venezuela is experiencing a complex economic crisis that limits the ability of its citizens to mobilize due to the lack of gasoline, monetary liquidity, and failures in basics services, suggesting that the economic activity of the countries will also influence the number of infections.