Looking through a google images search on Halkidiki (my usual method for spotting boulders), everything looks pretty flat and non-rocky.
Found this quote from a holiday site re local sports;
sailing, scuba diving, water skiing, climbing, windsurfing, canoeing, cycling, tennis, walking, jet ski, aqua park, trekking, snow skiing, snow boarding, snorkelling, swimming, flora & fauna, sea fishing, bungy jumping
If I dont find any climbing I can always go snowboarding!