The First Minister spoke out after reported outbreaks in Spain which is to form an "air bridge" with Scotland from Thursday meaning no quarantine is required for travellers arriving from the Iberian state.
Ms Sturgeon warned Scots it could mean restrictions are re-imposed and would apply to any country where the virus appears to be on the rise.
Croatia, France, Germany and the Netherlands are among the nations where quarantine-free travel to Scotland currently applies.
Bu Ms Sturgeon said: "You cannot book a holiday right now with certainty right now that none of this changes. I wish you could, I wish I could give you that certainty, but I can't.
"If you book a holiday to Spain because you think that in two weeks time or three time the quarantine arrangements might not apply, there's no guarantee of that.
"And there's no guarantee that the country you go to, if they have an outbreak, won't impose further measures while you are there.
"That all leads me to the very reluctant conclusion that says you should think very carefully right now about overseas travel if it's not essential. If you want a holiday, holiday here in Scotland."
The SNP leader has faced questions over the decision to add Spain to the countries after emerging reports which suggest its infection rates are now higher than hen the Scottish Government initially refused to add the country to a list of air bridges.
Ms Sturgeon said today that prevalence rates were 0.028, about 28 per 100,000, for Scotland, compared with 0.33 in Spain - about ten times higher - when the initial decision was made.
"The most recent prevalence data, we get this data through the joint bio-security data arrangements, the most recent data we have for Spain is 0.015 which is much more in line with what we assess Scotland's to be right now."
Ms Sturgeon said there is always a "lag" with this data and acknowledged that the situation in parts of Spain is volatile at the moment.
"We are seeing parts of Spain with rising prevalence," she added.
"It's possible that that prevalence rate in Spain is increasing again and that is why we have to keep this under review."
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