(Sept 7) Sea reached record high in pre-market trading Tuesday.
The move will be the first expansion into European e-commerce for the $190 billion Singapore-headquartered technology group, whose gaming arm Garena is already active in the region.
Shopee is simultaneously preparing to launch in India, Reuters reported last week, after aggressively expanding in Latin America since earlier this year.
One of the sources told Reuters that Shopee is cautiously scaling up its global expansion by testing out possible new markets.
The two sources, who requested anonymity because they were not authorised to speak to media, said Shopee will also launch in Argentina in the coming months.
The firm is already the dominant player in e-commerce in Southeast Asia, according to market researchers, bringing in $1.2 billion globally in revenue for the quarter ending June 30.
Polish news website Wiadomoscihandlowe.pl first reported the Shopee expansion into Poland. Sea did not immediately answer a Reuters request for comment.
Market research firm Euromonitor estimates the Polish e-commerce market to be worth 16 billion euros ($19 billion), with significant room for growth compared to Western countries.
Amazon launched its local website this year, while the biggest home e-commerce firm Allegro is ramping up installation of its own parcel lockers.