The decision means citizens can freely travel to Poland from Germany, Lithuania, the Czech Republic and Slovakia, and without being subjected to a quarantine period.
However, Poland’s external European Union borders – those with Belarus, Russia and Ukraine – remain closed. The European Commission is recommending these should open from July 1.
Meanwhile, Lithuania lifted controls at its crossings with Poland on Friday.
In a bid to curb the spread of the COVID-19 epidemic, Poland temporarily closed its borders to most non-residents on March 15.
The first infection was confirmed by Polish authorities on March 4, while the country's first coronavirus fatality was announced on March 12.
Poland declared a "state of epidemic". International scheduled flights and passenger rail connections were suspended in mid-March.
But since then a swathe of lockdown rules has been loosened.
The government has lifted restrictions on how many people can gather in places such as retail outlets, restaurants and churches, though some social distancing measures are still required.
Earlier this week, announcing that Poland would reopen its borders with its EU neighbours at the weekend, Prime Minister Mateusz Morawiecki also said that international flights would be allowed to resume to European countries from June 16.
Morawiecki told reporters that Poland needed to restore trade relations with the European Union as quickly as possible.
He added: "We’re at an important moment in the battle against the coronavirus... We don’t know what the situation will be in a month, two or three. But today we can say that we’re managing risk in the right way."
Data shows that with 31 COVID-19 deaths per million population, Poland appears to have been far less affected by the coronavirus than many other countries in Europe.
Officials said on Friday that a total of 28,577 people have tested positive for the COVID-19 disease in Poland, with 1,222 deaths from the coronavirus so far.