To enter Ecuador, travelers have had to present a negative COVID-19 test result and quarantine for 14 days. But, as of August 15, visitors can skip quarantine by presenting a negative COVID-19 test result with the results issued no longer than 10 days before arrival.
There is no restriction on the country of origin for international flights, but travelers must fill out a health form before arrival. Also, President Moreno extended the state of emergency through September 15, hence extending traffic restrictions and curfews. Note: the Galapagos Island have entirely different entry requirements.
Source: Travel OFF Path