Background The Coronavirus disease (COVID-19) pandemic invoked the government’s declaration of state of emergency nationwide taking effect from March 26 to April 30, 2020 in Thailand. The country promoted the public health campaign “Stay Home, Stop the Virus, For the Country” hoping to bend down the epidemic curve. This research aims to assess people’s adherence to such lockdown measures in order to provide recommendations for policy adjustments based on the changing situations from population’s side as well as inform the results and recommend desirable behaviours to the general public. Methodology We used online survey platform run by Google Forms service. Questionnaires were adjusted every week throughout the survey period from April 2-30, 2020 making four sets of questionnaires in total. Population were recruited by convenient sampling advertised through communication channels of various public or ganisations and social media influencers. Results These surveys achieved 99,865 respondents in total. Key demographic data were: 28.4% male and 71.6% female; average age of 42 years; and 84.8% holding bachelor’s degree or higher. We found that 99.8% understood how to follow “Stay Home, Stop the Virus, For the Country” campaign and 93.7% believed that such measure could slow down the outbreak. As much as 53.0% of respondents reported they stayed home all day whereas the main reasons among those who went out were going to work (62.3%) and doing necessary activities such as buying consumables or seeking healthcare (62.1%). The support needed most to make staying home possible was discounted utility bills (35.4%). The surveys showed that Personal Prevention Indices, a geometric mean of five desirable behaviours namely 2-metre physical distancing, wearing face mask, hand washing, avoid touching face, nose, eyes and mouth, practicing good food hygiene, were 0.70, 0.76, 0.75, and 0.78 respectively for Weeks 1-4. Most respondents (80.2%) agreed to have state/local quarantine located in their residing communities. Household’s economic impact was observed as 43.3% of respondents found experiencing income loss in Weeks 1-2 and 52.1% in Weeks 3-4. In addition, 49.1% of respondents believed their provinces were not ready for easing lockdown restrictions and 60.1% stated that they could bear living with these measures for additional four weeks or longer after April. However, 22.3% of the respondents planned to travel out of their residing provinces within a week should the government allowed. Conclusion The public health campaign “Stay Home, Stop the Virus, For the Country” achieved good adherence by the public in terms of trying to stay home and practicing personal preventive behaviours although a significant number of people facing detrimental impact on incomes. Overall, people did not believe the country was ready for easing lockdown and could accept this strict policy for at least another month after April. We propose the following policy recommendations: continue promoting the stay home policy and personal prevention behaviours; considering easing lockdown based on risk of transmission and essential activities for daily lives as well as preparing adequate state/local quarantine; and continue monitoring people’s behaviours until the situation becomes desirable.