The closest beach to Olive (Sithonia) is Anthemo Beach, just 360 m away. Within 15 km there are 33 beaches; below are the 12 closest to Olive, ordered by distance. Photos, map, reviews.
360 m from Olive

610 m from Olive

1.7 km from Olive

3.2 km from Olive

3.2 km from Olive

4.1 km from Olive

4.8 km from Olive

5.7 km from Olive

6.4 km from Olive

6.5 km from Olive

6.8 km from Olive

7.0 km from Olive

Anthemo Beach, just 360 m from Olive. The rest are listed below, ordered by distance.
Within 15 km of Olive there are 33 beaches, with 69 across Sithonia in total.
Based on user reviews: Karydi (★4.5), Lagomandra Beach (★3.8), Castello Beach (★3.8).
The beaches are spread out around Olive. A car makes exploring much easier — local buses and taxis are limited outside peak season.
Olive is on the Sithonia side of Halkidiki, in northern Greece. The nearest airport is Thessaloniki (SKG); from there a car is the most convenient way to reach the Sithonia villages.