Estonia, Latvia and Lithuania will create a shared "travel bubble" on Friday to allow people to move between them without going into quarantine, in a scheme that other regions may mimic as they lift coronavirus-related restrictions.
Its progress will be closely followed across Europe, as the Covid-19 outbreak eases and countries seek to reopen their borders to revive trade and travel, bring in seasonal workers and salvage the summer holiday season.
The three Baltic states have registered a combined total of 4,231 cases of Covid-19 and 135 deaths from the virus, and on Thursday they announced just 24 new infections between them.
Their handling of the pandemic has given their governments confidence to create the travel bubble for people on their territory, but anyone entering from outside will still have to observe two weeks of quarantine.
"It's a big step towards life as normal," Estonian prime minister Juri Ratas said when announcing agreement on the project last week.
His Lithuanian counterpart Saulius Skvernelis said the Baltic countries had "showed a good example by stating, very clearly, that only countries which successfully dealt with the situation can open themselves up".
"It's an opportunity for businesses closed to reopen, and a glimmer of hope for people that life is getting back to normal. We hope Poland and Finland [will] join this reopening soon."
Further south, the Czech Republic and Slovakia have kept the coronavirus outbreak under control and are now lifting many restrictions.
Buses and trains
The Czech government removed a ban on cross-border bus and train travel and the arrival of foreign seasonal workers this week, and it is discussing how to re-launch travel with neighbouring states and with popular holiday destinations such as Croatia.
Amid talks with Austria and Slovakia, Czech prime minister Andrej Babis said this week that "it could somehow work out that on June 8th or 15th, our three countries would open together".
German chancellor Angela Merkel has said she hopes her country and the rest of the EU's "passport-free" Schengen zone can start lifting border controls from June 15th, which is when Austria intends to fully reopen its frontier with Germany.
Switzerland has also announced plans to open its borders with Germany, France and Austria on that date.
Croatia, which relies on tourism for about a fifth of its gross domestic product, has already eased entry rules for foreigners who own property or boats in the country, and has discussed creating “corona corridors” through neighbouring states to help people get safely to the Adriatic coast.
"Our thoughts are now turning toward summer and to the places that we love to travel," European Commission executive vice-president Margrethe Vestager said this week. "That means taking gradual, careful steps to help travel restart in line with what science tells us."
