While 60 per cent of adults felt safe meeting with someone outside their household in the open air, this fell to 36 per cent when it came to visiting garden centres.
Parks continue to provide a refuge for many households, particularly those who do not have their own garden.
Almost half of those surveyed (49 per cent) had visited a public green space this week, with exercise among the most common reasons for going out.
The Transport Secretary announced this week that face coverings would be obligatory on public transport in England from June 15, including on buses, trams, trains, coaches, aircraft and ferries.
Yet the majority of Britons appear to be comfortable not wearing them in less crowded environments, the survey suggests.
Only 28 per cent said they used a protective mask outside their home in the last seven days, with people most likely to wear them when shopping.
Only 40 per cent of adults in employment left the house to go to work in the last week, an ONS study has revealed.
Guidelines are being drawn up to ensure workplaces are "Covid-19 secure", and those who cannot do their job at home are being encouraged to go back to work.
However, as lockdown restrictions gradually ease, only four per cent more people (40 per cent) are returning to their jobs compared with the previous week (36 per cent), the data shows.
At the same time, confidence of parents in sending their children back to school this month remains low.
Almost two thirds (63 per cent) are not happy to let them return to the classroom in June, according to the survey of 1,224 people in Britain.
Despite this uneasiness, Britons are generally feeling increasingly safe when venturing outside their homes, with the proportion of those comfortable going out rising from 33 per cent to 41 per cent this week.
Level of comfort varied depending on the activity, the survey suggested.
Groups of up to six people from different households are now able to meet outdoors, or in a garden, while continuing to practice social distancing with those who do not live in the same household.