Soviet-made missile boats of the project 205 Tsunami (NATO code: Osa I) entered service in the Polish Navy in the 1964. 13 of them were delivered between 1964 and 1975, initially in the 3rd Torpedo-Boat Brigade, and later (after reorganization) in the 3rd Warship Flotilla in Gdynia-Oksywie port. First one of them was decommissioned in 1986, four between 1989 and 1990 (three of them were transferred to the Coast Guard), one in 1993 and the rest between 2000 and 2006.
Polish 205's were slightly different from the standard ones: they were armed with additional East German FAM (FASTA-4) SAM launcher (with 9K32 Strela-2 missiles - spare missiles were stored in enlarged structure under MR-104 radar), normally installed only on some Osa-II boats and had additional mast for VHF communications (among those more visible differences).
As mentioned, three boats (Gdynia, Szczecin and Elbląg) were transferred to the Coast Guard and significantly rebuilt between 1990 and 1991, losing 30mm's (replaced by double 25mm cannon) and missiles, along with associated equipment. Also their interiors were heavily modified. Their service in the Coast Guard was initially meant to be only to be a stop-gap measure until arrival of the large patrol craft of the project 924, but these new ships were never made, and operating of the 205's as patrol boats proved hugely uneconomical, therefore they were all decommissioned in 1995.