Clothes to wear whilst swimming?
In the name of Allah, the most Beneficent, the most Merciful.
It should be borne in mind that one can attend swimming baths where there is no intermingling of sexes.
In the Holy Quran, Allah (SWA) has said:
‘O Nabi, say to the believing men to lower their gaze and guard their modesty’
(Surah Noor v.30)
It is narrated by Saaidah Umme-Salamah Radialahu Anha that she was with the Prophet of Allah Sallallahu Alahi Wasalam and Saaidah Maimunah Radiallahu Anha when Saaiduna Ibn Umme Makhtum Radiallahu Anhu (a blind sahabi) came to the Prophet of Allah Sallallahu Alahi Wasalam after the order of Hijab was revealed. The Prophet of Allah Sallallahu Alahi Wasalam said to his wives to seclude themselves from him. They replied that he was blind and could not see them. The Prophet of Allah Sallallahu Alahi Wasalam replied: “Are you blind! Can you not see him?”
(Sunan Tirmizi)
With regards to your question, if there are male only sessions then you can attend the swimming baths as long as the area from your belly button to your knees (including your belly button and kness) is covered. (Raddul Muhtar p.76 v.2)
As for women, they should only attend women only sessions. As there will be a mix of Muslim and non-Muslim women, she should wear a swimsuit which covers her entire body except for her face, hands and feet. (Raddul Muhtar p.534 v.9)
Only Allah Knows Best
Mohammed Tosir Miah
Darul Ifta Birmingham