According to Airlineroute:
Air Corsica will operate three routes from STN in S18 using A320:
Ajaccio – London Stansted eff 03MAY18 2 weekly (Day 47, 3 weekly Day 467 from 01JUN18 to 09SEP18)
Bastia – London Stansted eff 03MAY18 2 weekly (Day 47, 4 weekly Day x123 from 20JUL18 to 05SEP18)
Figari – London Stansted eff 02JUN18 1 weekly (Day 6, 2 weekly Day 36 from 05SEP18)