[kazeem]

And it was narrated from the Prophet SAWS (peace and blessings of Allaah be upon him) that a man should cover his ‘awrah except from his wife and female slave (concubine). It was narrated that Bahz ibn Hakeem said: my father told me from my grandfather, who said: “I said, ‘O Messenger of Allaah, with regard to our ‘awrah, from whom should we cover it?’ He said, ‘Cover your ‘awrah from everyone except your wife or (the slave woman) whom your right hand possesses.’ He asked, ‘What if a man is with another man?’ He said, ‘If you can avoid letting anyone see that, then do that.’ He asked, ‘What if a man is on his own?’ He said, ‘Allaah is more deserving that he should be modest before Him.’” (Narrated by al-Tirmidhi, al-Adab, 2693; classed as hasan by al-Albaani in Saheeh Sunan al-Tirmidhi, no. 222). The hadeeth indicates that a person should cover up when he is alone. And Allaah knows best.

http://www.islam-qa.com/en/ref/13698/naked


er fragte: was ist wenn ein mann alleine ist? er antwortete: allah verdient es am meisten das man sich vor ihm sittsam kleidet

eine frau darf ebenso nicht die aurah der frau sehen, also beim schwimmen muss ebenso die aurah der frau bedeckt sein...

"der mann soll nicht die aura des mannes anschauen und die fraue nicht die einer frau. der mann soll nicht unter einem gewand mit einem mann sein und auch nicht die frau mit einer frau unter einem gewandt"
sahih muslim, hadith nr. 338

noch eine fatwa zum schwimmen
http://www.islam-qa.com/en/ref/1075/swim