i used to go to the east side of the baltic coast.i 'd like to recommend you a few places on the beautiful HEL peninsula(very narrow and long peninsula,covered with a beautifull forrest).check for jurata or jastarnia.there is an open sea on the north side and gdanska bay on the south side of the peninsula.it has calm and shallow waters enabling easy surfing and swimming.perfcect for watersports and birdwatching(passing birds in the autumn in spring)
also;my brother was in jastrzebia gora which is close to the peninsula and loved this place.there is a site which may help you to find a nice and quiet place there
ring the number.they speak english and german