The Polish Navy has five submarines. The Kilo is ORP Orzeł. It joined the Polish fleet in 1986 and serves with the Polish 3rd Flottila. As Kilo class submarines go they're very standard.
The other four submarines are ORP Kondor (Kunna), ORP Sęp (Skolpen), ORP Sokół (Stord) and ORP Bielik (Svenner). The name in parenthesis isn't their name translated into another language, it's their name when they were still in the Royal Norwegian Navy.
The ships are Kobben Class Submarines (replaced by Ula in Norwegian service, and in turn are being replaced). The Kobben was also tranfered to the Royal Danish Navy where they are now out of service. The class is also known as Type 207.
As far as submarines go they are small and quiet at just 47 meters in length and displacing 485 tons submerged. They have eight 553 torpedo tubes and can accommodate external and internal mines. They can't accommodate modern torpedoes and as a result are left with 1960s era models like Mark 37:
The Kobben class is both slow and low on endurance, with a max speed of 18kn and range of 4200nmi, half of what an Ula can do. But given Poland's territorial and regional waters, this is fine for a wait and watch or ambush operation. They have limited ability to support allied operations outside of the Baltic and North Seas, but if refueled can make extended patrols in the Mediterranean as well.
While still serviceable they are getting very old as the first ship of the class - S315 Kaura - was commissioned in 1965 (While the lead ship of the class Kaura was actually delayed one year). The Polish boats were commissioned between 1964 and 1967, but until 2001 served with the Royal Norwegian Navy (transfer to Poland in 2002 and 2003).
Poland is exploring a joint build/buy with the Royal Norwegian Navy to replace each nation's Ula and Kobben class submarines respectively. So far no details are known publically about that plan or if Norway will consent to Poland joining their tender.