Praise be to Allaah.
The ‘awrah of a man is the area between the navel and the
knee; as for the navel and the knee themselves, they are not part of the
‘awrah.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
There are several opinions concerning the matter:
One is that the knee is included in the ‘awrah so it must be
covered.
The second opinion is that the navel and the knee are both
part of the ‘awrah so they must both be covered.
The third opinion – which is the well-known view among our
madhhab – is that the navel and the knee are not included in the ‘awrah, so
they do not have to be covered. This is based on the definition of the
‘awrah as being “between the navel and the knee.”
End quote from ash-Sharh al-Mumti‘, 2/160
He also said (may Allah have mercy on him): The ‘awrah for a
man is the area between the navel and the knee.
End quote from ash-Sharh al-Mumti‘, 5/273
An-Nawawi (may Allah have mercy on him) said: Concerning the
‘awrah for men, there are five opinions; the correct view is that it is the
area between the navel and the knee, and the navel and the knee are not part
of the ‘awrah.
Our evidence for that is what we have quoted above from
Abu’d-Darda’ (may Allah be pleased with him) who said: I was sitting with
the Prophet (blessings and peace of Allah be upon him) when Abu Bakr (may
Allah be pleased with him) came, holding up the hem of his garment to such
an extent that his knees showed. The Prophet (blessings and peace of Allah
be upon him) said: “Your companion has had a quarrel.” And he quoted the
hadeeth.
Narrated by al-Bukhaari
It was narrated from Abu Moosa (may Allah be pleased with
him) that the Prophet (blessings and peace of Allah be upon him) was sitting
in a place where there was water and his knee or knees were uncovered, then
when ‘Uthmaan came in, he covered them.
Narrated by al-Bukhaari. And we have quoted above hadeeths
which speak of the thigh being ‘awrah.
End quote from Sharh al-Muhadhdhab, 3/174, 175
For the rest of the evidence please see the answer to
question no. 34976
And he said in ash-Sharh al-Kabeer, 1/457: The navel
and the knees are not part of the ‘awrah. This is the view of Maalik and
ash-Shaafa‘i. End quote.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: It
is not permissible for a young man to play football, for example, wearing
only shorts that do not reach the knees or that do not reach the navel. It
is essential that the area between the navel and the knee be covered in the
case of young men.
End quote from Liqa’ al-Baab al-Maftooh, no. 73
Based on that, it is permissible to go to the sea wearing
clothing that covers the area between the navel and the knee. But if it
leaves any part of the thigh or anything lower than the navel uncovered,
that is not permissible.
But if that is in a place where there is mixing, it is not
permissible because that involves staying in a place where evil actions are
being committed when one is not able to change them or denounce them.
And Allah knows best.