On Saturday, 27,000 refugees from Ukraine arrived in Poland, according to the agency.
Meanwhile, a total of nearly 5 million people left Poland for Ukraine, including 29,000 on Saturday, the Border Guard noted.
A deputy interior minister said last month that Poland was home to some 1.3 million Ukrainians after many refugees from Russia's invasion of Ukraine decided to return to their country.
Poland in March passed a bill that offers wide-ranging support to Ukrainians escaping the Russian invasion of their country, which began on February 24.
The measure grants them residence rights and ensures access to education, healthcare and social benefits.
Eighty-one percent of Poles are in favour of accepting refugees from war-torn Ukraine, according to a recent survey.
Sunday is day 221 of the Russian invasion of Ukraine.