The organization, formed in 1963, purports to represent more than 115,000 Muslim students across the UK.
Osman, originally from the Netherlands and was a former student at the University of Warwick, before becoming president of FOSIS in 2014.
Though little is known about his death, Osman had reportedly drowned in a river in the Landquart District of Graubünden, Switzerland, after a boat he was traveling in capsized.
In a statement released by the FOSIS National Executive Comittee, a spokesperson said:
On Saturday 4th July, whilst away in Switzerland visiting colleagues from the Federation of Muslim Youth and Student Organisations (FEMYSO), Bashir passed away in a drowning incident having fallen under rough waters for over 10 minutes. By the time the rescue services found him, he was pronounced dead at the scene.
His passing in the blessed month of Ramadan and whilst drowning, one of the categories of martyrdom in Islam, are sources of comfort for all those who held Bashir dear to them. Bashir’s leadership, compassion, and commitment to serving his community and those less fortunate than him were inspiring traits that make his death such a grave and heartfelt loss to us all.
Following news of his death, friends and colleagues expressed their sympathies and memories on Twitter.
So sad to hear of the death of brother Bashir Osman, president of Fosis- thoughts and prayers with family. @BashirOsman88
— Mohammed Shafiq (@mshafiquk) July 4, 2015
— Azad Ali (@azadaliCCM) July 4, 2015
Still in shock Fosis's President Bashir Osman passed away today, a life lived for others may Allah swt accept him as a shaheed iA
— mahnoor bajwa (@mahnoorbajwa7) July 4, 2015
Many friends also highlighted the charitable work Osman was involved in while leading FOSIS
This was Bashir Osman charity campaign for East Africa before he passed away https://t.co/wNjEBoE7Oe
— Shafik Mandhai (@ShafikFM) July 4, 2015
In June, Bashir Osman said his first FOSIS NEC meeting of the year was "super productive with amazing plans" – honour him, see them through
— Habiba Hamid (@habibahamid) July 4, 2015
In a statement, Omar Ali, former FOSIS president said :
He was a man who made everyone smile and laugh.
He was a brother who cared for those around him. He was a Muslim who worked tirelessly to help humanity. He was an inspiration to the young and old all around the UK and Ireland. He had a unique ability to make so many feel special and hold a place in their heart for him.