Exe Valley Sprint Triathlon - 400m Pool Swim/25k Bike/5k Run

Exe Valley Novice Triathlon - 200m Pool Swim/20k Bike/2.5k Run

This is another popular Triathlon which fills up fast, normally by November. 

They also have a good Aquathlon series during the winter (swim/run).

For more details see Exeter Triathlon Club.