However, their teammate Erin Bond was denied the opportunity to compete.
Tolcon was first across the line in the 100m, 200m and 400m and helped the 4x100m and 4x400m relay teams to gold medals while D’Sylva won the 800m and 1500m.
Tolcon was also named the under-14 girls best athlete of the meet.
Bond qualified for the international event after winning the WA Little Athletics Championships high jump event for the fourth consecutive year.
The St Mary’s Anglican School for Girls student had warmed up for the event in Singapore on the second day of competition when an electrical storm forced it to be suspended.
Other UWA LAC athletes who won medals in Singapore included 14 girls competitor Liv Ridley (bronze triple jump and 200m hurdles, silver 4x400m relay) and 14 boys competitor Callum Jacobsen (bronze triple jump, silver javelin).
Winners in the 15s events included Zac Jurilj (bronze 800m, silver 1500m), Breanna Dusting (silver 800m, bronze 1500m) and Austin Bennington (silver javelin).