Lake Sarbsko (windsurfing/kitesurfing)

Shallow, sheltered, and often thermal, Sarbsko is considered one of the best training areas in Poland. It's an ideal place to safely start windsurfing or kitesurfing and progress quickly. There are schools with rental shops on the lake; during the season, they offer courses from beginners to advanced. A day on the water is a great way to combine it with an evening sunbathing in Łeba. 

Practically:
Bases/schools (examples): surf-sarbsk.pl, windsurfing-habenda.pl.
Access: Sarbsk (approx. 10 km). Reservations in advance during the season.