The combined media budget of Play and Netia makes it one of ZenithOptimedia Poland's largest clients. Netia owns 23.4 per cent of P4, which owns the Play brand.
The decision follows a four-month pitch process, which also involved Play's incumbent agency, PHD. Mediaedge:cia, which had previously handled Netia's media business, withdrew from the contest.
Jacek Hensler, the Play chief marketing officer, said: "We decided to co-operate with the most reliable partner which guarantees effective and efficient spending policy."