This year's event is spread over two days with the elite athletes vying for places in the 2023 world championships on the Saturday and the open competition on Sunday.
A golden sunrise greeted the early rising triathletes on Saturday morning. They completed the standard/Olympic version with a 1,500 metre swim in the mere, followed by a 40k bike and a 10k run.
On Sunday there is a choice of the standard, the sprint, half distance race, or the middle distance (2,000m swim, 78k cycle, 20k run).
Only one short stretch of lane behind the town's mere is closed during the races but Keith Hancock, race director for UK Triathlon, urged motorists to be aware of cyclists on local roads.
Organisers say the event brings several hundred competitors and their supporters to Ellesmere, helping the local economy.
And local organisations benefit with donations given by UK Triathlon in return for marshalling and stewarding.
Athletes from across the UK take part in the event each year but it also attracts triathletes from the town itself and from Shropshire and the Welsh border.
As well as individual events there is the chance to take part as a relay team.
The Shropshire Triathlon follows two sporting events in Ellesmere last weekend: a 10k race through the town centre on Sunday and the mere mile swimming event for the Robert Jones and Agnes Hunt Orthopaedic Hospital on Monday.
This weekend also sees Ellesmere Cricket Club's President's Day.