The Severn Mile event, which was organised by Shrewsbury Masters Swimming Club, took place yesterday in front of dozens of spectators.
Competitors donned wetsuits as they tackled the waters of the Severn in the sunshine, setting off from the jetty where the Sabrina Boat cruiser is normally moored.
Safety cover for the event was provided by officials from Shrewsbury Canoe Club. Entry to the event cost £10, with charity swimmers given free places.
Swimmers were able to either take on distances of 700 metres or 1,500 metres, with participants swimming from the Welsh Bridge to Kingsland Bridge, finishing at Pengwern Boathouse.
It is the sixth year the event had taken place, after it was first launched in 2008 with 13 swimmers taking part.
The first wave of swimmers set off at about 11am, followed by staggered groups depending on ability and speed.
Organiser Chris Myles said yesterday's event had gone well, despite heavy rain on Friday making conditions in the water challenging.
He said those taking on the challenge had welcomed the support from the sizeable crowds watching the event from the banks of the River Severn.
"We had about 140 to 145 swimmers on the day. The support from the crowd was excellent, especially between Kingsland Bridge and Pengwern Boathouse," he said.
"The river level was about 0.9 metres, which was about the same as last year – any more than that and some would have been struggling. One person did get out because it was a bit choppy.
"It was excellent. We have had probably half-a-dozen e-mails from people saying how excellent it was and that they will be back next year."
Open water swimming has grown in popularity since it was introduced as an Olympic sport at the Beijing Games in 2008.
Similar events have been taking place around the country, with open water swims happening in London, Manchester and Sheffield.
All of the swimmers who took on yesterday's challenge in Shrewsbury received a medal to recognise their efforts.