The water has 0-20°C. In winter a drysuit (if the water is not frozen), spring and autumn a thick wetsuit and in summer thin wetsuit with short sleeves or shorty.
From Kallax Airport, drive towards the city of Luleå. Then aim for the military base called F21. 200m from the gates of the military base turn right, then left within 500m. Drive until you see a cell mast on your right, turn left. Straight forward to the beach (now you see the beach and the water).